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Electric power, definition, units, formula with example

2020-10-13T20:53:00.002+05:30

Electric power, definition, units, formula with example

Friends, today we will read about electric power and know where it is needed and how we get it out. How important it is in our life.

Electric Power:-

1)The amount of electric energy consumed per unit time (1 sec) in any electrical or electronics appliance is called electric power.

P = E / T

P = Power

E = Energy

T = Time

2)Any electrical or electronics appliance will do as much work per unit time (1 sec), we call it electric power.

P = W / T

P = Power

W = Work

T = Time

It means to say that if the power of a device is more then it will work in less time and if the power of a device is less then it will take more time to work. Like suppose there are two water filled motors.

One motor is of 1 KW and the other motor is of 500 W, so we know that a motor of 1 KW will fill water quickly i.e. in less time and a motor of 500 W will take more time to fill water.

S.I Unit of electric power:-

We have read already P = E / T

We know that the S.I unit of electric energy (E) = joule

Than P = Joule / Second

P = J . S^-1(Watt)

The S.I unit of electric power is Watt (W)

We can say that power is said to be 1W if 1A current flows through a circuit having 1V pottential difference.

1W = 1V X 1A

1W = V . A

Formula of electric power:-

If an electronics or electrical device is running, then it is obvious that there is movement of electrons inside it. The movement of electrons means that the current in the device is moving.

The device will also be hot due to current movement. This means that electrical energy in the device is converting into heat energy. So we can also say power such as.

P = H / T

P = Power

H = Heat energy

T = Time

Heat (H) = I²RT

P = I²RT / T

P = I²R ------------ (i)

According to Ohm's law

V = IR

We can say that

R = V / I

Put the value of R in Eq (i)

P = I²R

P = I² V / I

P = V . I--------------(ii)

According to Ohm's law

V = IR

We can say that

I = V / R

Put the value of I in Eq (i)

P = I²R

P = V²/ R^{2 .}R

P = V²/ R-----------------(iii)

Commercial unit of electric power:-

The commercial unit of electric power is kilo watt hour (KWH) .

^{1KW = 1000 W}

^{1 Hour = 3600 Seconds}

^{1KWH = 1000 W X 3600 S}

^{1 KWH = 1000 Joule / Second X 3600 Second}

^{1KWH = 3600000 Joule}

1KWH = 36 x 10⁵J

^{Or we can say}

1KWH = 3.6 x 10⁶J

^{Solved Example}

Example - An electric bulb run from 220V mains. The current flowing through it is 0.5A. At which rate is the electrical energy transformed by bulb? How much energy is transformed in 6 hour?

Solution - Now read the question carefully and see what we have to find out of it. In this question, we have to find electric energy. So we know what is the formula of electric energy.

As you know P = E / T

Than E = P . T

We have been given time here but electric power is not given. So first we will find electric power. Here we have given the value of voltage and current to get electric power.

As you know P = V . I

P = 220 X 0.5

P = 110 W or J / S

Now we have found out electric power here and now we will also easily find electric energy. This bulb gives 110 W power in 1 second. First we will take 6 hours time of bulb.

1 minute = 60 sec

1 hour = 60 X 60 sec

1 hour = 3600 sec

6 hour = 3600 X 6 sec

6 hour = 21600 sec

Now we have found out time here and now we will also easily find electric energy.

E = P X T

E = 110 J/S X 21600 S

E = 2376000 Joule

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Two electric lamps are rated as 200 V 100w and 220v 40w respectively. Calculate electrical resistance

Series and Parallel combination of Resistance

V belt drive definition, types, design, advantage, disadvantage

2020-10-04T22:19:00.005+05:30

V belt drive definition, types, design, advantage, disadvantage

The V belt is used where a greater amount of power is required from one pulley to another and the distance between these two pulleys is very less. This belt is made of trapezoidal shape. This belt is made of fabric and cords moulded in rubber. Which is covered with fabric and rubber cover from outside.

The included angle under these belts is kept from 30 degree to 40 degree. This belt uses high force of friction to pull the pulley. This force of friction depends on the included angle under the belt. The force of friction is high when the angle is less, which causes wear and tear problem. Therefore a right included angle is required. There is always some clearance in these belts and pulleys.

Types of V belt :-

According to Indian standards (IS: 2494–1974), there are five types of V belt.

1) Type A

2) Type B

3) Type C

4) Type D

5)Type E

These five types are divided according to the power range.

Length of V belt :-

According to IS: 2494–1974, we describe V belt is in its type and nominal inside length. For example, if a V belt is of type A and its inside length is 1295 mm, then we will call it A1295 - IS: 2494. The length of this belt is always standard. We take its length unit in mm.

To take pitch length, we deposit in inside length such as 36 mm in type A, 43 mm in type B, 56 mm in type C, 79 mm in tpe D and 92 mm in type E.

Pulleys for V belt :-

The Pulley is used for this belt is made of cast iron or pressed steel. Grooves are cut in V pulley.

Face width (B) = (n-1) e + 2f

Advantages of V belt drive :-

This belt has long life.
These belts have greater shock tolerance when a machine is started.
This drive is positive because there is negligible slip between the grooves of the belt and the pulley.
This drive also works at higher Velocity ratio (Max. 10).
The center line of the pulley of this belt drive can be horizontal, vertical or inclined.
This belt is without any joint.

Disadvantage of V belt drive :-

These belts are not more durable than flat belts.
In this belt drive the construction of the pulley is more difficult, than the construction of the pulley of the flat belt drive.
We mostly face creep problems in this belt. So this is why we do not use this belt with constant speed like synchronous machine etc.
This drive is not used for long center distance because the weight per unit length increases due to the length.

Velocity Ratio :-

Let d₁ = Pitch diameter in metre of driver Pulley

d₂ = Pitch diameter in metre of driven Pulley

N₁ = Speed of driver Pulley

N₂ = Speed of driven Pulley

N₁/ N₂ =d₁/d₂

Power transmitted per belt :-

Let T₁ = Tension in belt on tight side (N)

T₂ = Tension in belt on slack side (N)

v = Speed of driver Pulley (m/s)

v = ∏d N / 60

Power transmitted per belt = ( T_{1 -}T₂ ) v in Kw

No. of V belts :-

No. of V belt = Total power transmitted / Power transmitted per belt

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JK flip flop diagram, excitation, characteristic, Truth table

2020-09-24T20:18:00.003+05:30

JK flip flop diagram, excitation, characteristic, Truth table

JK FLIP FLOP:-

Friends, the characteristics of JK flip flop are exactly like SR flip flop. J and K behave exactly like S and R, such as J as set and K as reset. When we work on SR flip flop, there is a case when J = 1 and K = 1, then indeterminate condition comes in SR flip flop. Due to which the result of this case is not known. To overcome this indeterminate condition, we use JK flip flop. In this flip flop, this indeterminate condition goes away and we get to know the result of this case. In Fig 1 you can see the symbolic diagram of JK flip flop. We will know about its different case and from these cases we will also design its truth table.

Fig 1. Graphical symbol of JK flip flop

WORKING OF JK FLIP FLOP:-

We will understand the working of JK flip flop with the help of NAND gate as you see in fig 2. We have divided the working of JK flip flop in some cases.

Fig 2. JK flip flop using NAND gate

CASE 1:-

When J = 0, K = 0, Q = 0, Q+1 = ?

As given in Fig 3. When J = 0, the output of NAND gate 1 directly will be '1'. Similarly if K = 0, the output of NAND gate 2 directly will be '1'. In this case if we keep the value of Q as '0', then '0' will go to the input of NAND gate 4 so that the output of NAND gate 4 will be '1'. Now this '1' will go to the input of NAND gate 3 and the output of NAND gate 3 will be '0'. Now we have got the value '0' of Q + 1.

Fig 3

CASE 2:-

When J = 0, K = 0, Q = 1, Q+1 = ?

As given in Fig. 4. When J = 0, the output of NAND gate 1 directly will be '1'. Similarly if K = 0, the output of NAND gate 2 directly will be '1'. In this case, if we keep the value of Q as '1', then '1' will go to the input of NAND gate 4, so that the output of NAND gate 4 will be '0'. Now this '0' will go to the input of NAND gate 3 and the output of NAND gate 3 will be '1'. Now we have got the value '1' of Q + 1.

Fig 4

CASE 3:-

When J = 0, K = 1, Q = 0, Q+1 = ?

When J = 0, the output of NAND gate 1 directly will be '1'. Similarly, if K = 1, then as the value of Q in Fig 5 is kept '0', now this value will go to the input of NAND gate 2. We have given the value of Q to the input of NAND gate 2 because K = 1. Due to this the output of NAND gate 2 will be '1'. The value of Q which is '0' will go to the input of NAND gate 4 and thereby the output of NAND gate 4 will be '1'. Now this '1' will go to the input of NAND gate 3 and the output of NAND gate 3 will be '0'. Now we have got the value '0' of Q + 1.

Fig 5

CASE 4:-

When J = 0, K = 1, Q = 1, Q+1 = ?

When J = 0, the output of NAND gate 1 directly will be '1'. Similarly, if K = 1, then as the value of Q in Fig 6 is kept '1', now this value will go to the input of NAND gate 2. Due to this the output of NAND gate 2 will be '0'. The value of Q which is '1' will go to the input of NAND gate 4 and thereby the output of NAND gate 4 will be '1'. Now this '1' will go to the input of NAND gate 3 and the output of NAND gate 3 will be '0'. Now we have got the value '0' of Q + 1.

Fig 6

CASE 5:-

When J = 1, K = 0, Q = 0, Q+1 = ?

When J = 1, then as in Fig 7 if the value of Q is kept as '0' then the value of Q̅ will be '1'. We have given the value of Q̅ to the input of NAND gate 1 because J = 1. Now this value will go to the input of NAND gate 1. This will cause the output of NAND gate 1 to be '0'. Similarly if K = 0, the output of NAND gate 2 directly will be '1'. The value of Q which is '0' will go to the input of NAND gate 4 and thereby the output of NAND gate 4 will be '1'. Now this '1' will go to the input of NAND gate 3 and the output of NAND gate 3 will be '1'. Now we have got the value '1' of Q + 1.

Fig 7

CASE 6:-

When J = 1, K = 0, Q = 1, Q+1 = ?

When J = 1, then as in Fig 8 if the value of Q is kept as '1' then the value of Q̅ will be '0'. Now this value will go to the input of NAND gate 1. Due to this the output of NAND gate 1 will be '1'. Similarly if K = 0, the output of NAND gate 2 directly will be '1'. The value of Q which is '1' will go to the input of NAND gate 4, which will cause the output of NAND gate 4 to be '0'. Now this '0' will go to the input of NAND gate 3 and the output of NAND gate 3 will be '1'. Now we have got the value '1' of Q + 1.

Fig 8

CASE 7:-

When J = 1, K = 1, Q = 0, Q+1 = ?

When J = 1, then as in Fig 9 if the value of Q is kept as '0' then the value of Q̅ will be '1'. Now this value will go to the input of NAND gate 1. This will cause the output of NAND gate 1 to be '0'. Similarly, if K = 1, the value of Q which is '0' will go to the input of NAND gate 2. Due to this the output of NAND gate 2 will be '1'. The value of Q which is '0' will go to the input of NAND gate 4, which will cause the output of NAND gate 4 to be '1'. Now this '1' will go to the input of NAND gate 3 and the output of NAND gate 3 will be '1'. Now we have got the value '1' of Q + 1.

Fig 9

CASE 8:-

When J = 1, K = 1, Q = 1, Q+1 = ?

When J = 1, then as in Fig 10 if the value of Q is kept as '1' then the value of Q̅ will be '0'. Now this value will go to the input of NAND gate 1. Due to this the output of NAND gate 1 will be '1'. Similarly, if K = 1, the value of Q which is '0' will go to the input of NAND gate 2. Due to this the output of NAND gate 2 will be '1'. The value of Q which is '1' will go to the input of NAND gate 4, which will cause the output of NAND gate 4 to be '1'. Now this '1' will go to the input of NAND gate 3 and the output of NAND gate 3 will be '0'. Now we have got the value '0' of Q + 1.

Fig 10

There is a table design based on these eight cases, which we call the present state to next state table for JK flip flop, which you can see in Fig 11.

Fig 11. Present state - Next state table for JK flip flop

TRUTH TABLE OF JK FLIP FLOP:-

The truth table of JK flip flop is the extract of these eight cases which we have read above. As given in Fig. 12.

Fig 12. Truth table for JK flip flop

1) When the value of J and K is '0' and if we take the value '0' of Q then we get Q + 1 output '0' and if we take the value '1' of Q then we get Q + 1 Output '1' is available only. So to say this means that we are getting Q only from the value of Q.

2) When J = 0 and K = 1, the value of Q is always output '0' at '0' and '1'.

3) When J = 1 and K = 0, the value of Q is always output '1' at '0' and '1'.

4) When the value of J and K is '1' and if we take the value '0' for Q then we get Q + 1 output '1' and if Q takes the value '1', then we get Q + 1. Only output '0' is available. So to say that we are getting Q̅ from the value of Q means that we are getting the complement of Q.

CHARACTERISTIC EQUATION OF JK FLIP FLOP:-

We will design a K-map based on the present state to next state table in Fig 11. Then from this K-map we will find the characteristic equation of JK flip flop. Please see the Fig 12 for K-map.

00 = J̅ K̅ 0 = Q̅

01 = J̅ K 1 = Q

11 = J K

10 = J K̅

Fig 13. K-map for JK flip flop

The characteristic equation for JK flip flop is

Q+1 = Q̅ J + Q K̅

Cement grinding and manufacturing plant process

2020-09-17T12:03:00.195+05:30

Cement grinding and manufacturing plant process

Cement Grinding Plant

For making cement, we requires clinker, clay, gypsum or flyash. If we want to make OPC cement then we will use gypsum. If we have to make PPC cement then we will use Flyash.

"Factory of National Cement Share Company by DFID - UK Department for International Development, Wikimedia Commons, CC BY 3.0

Cement grinding plant is divided into five sections.

1) Storage Yard section

2) Proportioning Hopper section

3) Cement Mill section

4) Cement Silo section

5) Packing section

1) Storage Yard section :-

Storage yard should be designed in such a way that raw material can be stored for 7 -10 days. In this section, raw material brought from outside is stored. Raw material may contain clinker, clay, gypsum or flyash and additives. All these have different storage yards.

Charnwood Brick – 1 – Clay conveyor entering the works
cc-by-sa/2.0 - © Alan Murray-Rust - geograph.org.uk/p/5857633

The storage yard consists of ground hoppers. At the bottom of ground hopper has a pin gate or slide gate.. Which prevent the material from escaping. This is followed by vibratory feeders. Which put the material on the belt conveyor. This belt conveyor feeds to the proportioning hoppers.

2) Proportioning Hopper section:-

The hoppers in this section are made of mild steel or cement concrete. The capacity of these hoppers is prepared at the base of the percentage of material. For example, the percentage of clinker is most commonly used to make cement. Therefore the hopper of the clinker is of the largest size.

Hanson Cement, Clitheroe
cc-by-sa/2.0 - © Alan Murray-Rust - geograph.org.uk/p/4480158

Other hoppers have a lower capacity, such as gypsum / flyash, clay and additives. The material on these hoppers is inserted with the help of reversible belt conveyor or three way chute. All these hoppers are fitted with pin gate or slide gate. For example, clinker and gypsum for slide gate, flyash and clay for pin gate are used.

The weigh feeder is used to extract the appropriate quantity of material. All materials are inserted on the belt conveyor with the help of chute. This belt conveyor feeds the cement mill. In the proportioning hoppers, venting connection must always be given. Venting greatly reduces the problem of chocking. Apart from this, also keep in mind that it is very important to provide a manhole connection in Proportioning hoppers so that it can be repaired from time to time.

In MS hoppers, liner should always be used for abrasive material to avoid hopper wear. Nowadays, high level and low level indicators are also being provided in Proportioning hoppers. A poking hole must be provided in the tapper portion of the hoppers so that the largest size of the material can be broken with the help of rod which hinges the outlet of the hoppers.

3) Cement Mill section:-

Mill section is the main part of cement plant. It can also be called the heart of an entire plant. We also know Mill section as cement mill section. If we talk about cement mill section, then there are two types.

a) Open circuit b) Close circuit

a) Open circuit:-

The cement mill section in which classifier is not used is called open circuit.

b) Close circuit:-

The cement mill section in which classifier is used is called close circuit.

Closed circuit cement grinding comprising an 18’ diam. air separator and a 2600 HP ball mill in Portugal. by N.N.Zoubov Engineers, Wikimedia Commons, CC BY-SA 3.0

Process :-

A two way chute is placed at the discharge end of the belt conveyor which brings the material from the hopper section. One end of the two way chute is attached to the cement mill, while the other end is kept open to check the composition of the material.

Proper lining of two way chute should be done so that it does not wear. In the cement mill the material is converted into fine powder. This is where cement is manufactured. The fineness of cement depends on the Blaine.

The capacity of cement mill depends on the capacity of the plant such that if the capacity of the plant is 800 TPD then the capacity of the mill will be 800/20 = 40TPH. After the cement mill, an air slide or screw conveyor is attached which is connected to the outlet of the cement mill through the chute and which is connected to the inlet of the bucket lift through the chute.

In the close circuit, the bucket elevator sends the material to the classifier via air slide. The classifier separates the coarse and fine material. The coarse material is again poured into the mill via air slide while fine material is sent to the cyclones. On the other hand, if we look in the open circuit, the material is sent directly from the bucket elevator to the cyclones.

The rotary vane feeder (RVF / RAL) is attached below the cyclones. A fine air slide is attached to the rotary vane feeder which is connected to the bucket elevator or air lift feeding in silo.

4) Cement Silo section :-

The fines air slide which comes from the cement mill section and feed the bucket elevator, the same bucket elevator feed into the silo top air slide. Many plants do not install silo feeding bucket elevator.

Cement Silos by 长城建机编辑处 , Wikimedia Commons, CC BY-SA 4.0

Air lift is used in those plants. Air lift lifts the fine material and poured into the expander. From expander the material goes into the silo feed air slide. Silo is made of Mild steel or concrete. A bin mounted dust collector is placed on the top of the silo, so that there is no problem of dusting and chocking.

A high level indicator is placed at the top of the silo. So that the cut can be made after the silo is filled. With this, you should also know that there are two types of silo, one flat bottom type silo and the other conical bottom type silo.

In Silo we store material for two to three days. The capacity of silo depends on the capacity of the plant. If the plant capacity is 800 TPD, the maximum capacity of silo will be 800 X 3 = 2400 tonnes. The areation system is provided inside the bottom part of the silo so that the cement does not get frozen in the bottom and easily exits through the outlet. The slide gate and rotary vane feeder are fitted under the silo.

5) Packing section:-

The cement is packed in bags in the packing section. Many small plants do not have a separate packing section. In small plants, packing is done using a packing machine just below the silo. There are two types of packing machine, one stationary packing machine and the other rotary packing machine / rotary packer.

The storage bin is attached before the packing machine, so that the material pressure directly from the silo does not affect the packing machine. A high level indicator is put in the storage bin. Proper venting of packing machine and bin is very important.

Proper venting should also be given to the packing area, as a result there is no dust in that area and in it can be worked easily. The bag which is filled in the packing machine is put on the truck loading belt conveyor or truck loading machine through the chute conveyor. These truck loading belt conveyor or truck loading machine load the bags into the truck by the workers.

Through these sections, cement is prepared and reaches all of us.

Common Emitter configuration of transistor, characteristics, application

2020-09-13T22:53:00.001+05:30

Common Emitter configuration of transistor, characteristics, application

Friends, today we will read about the common emitter configuration of BJT transistor. In this lecture, we will know its diagram, its characteristics and its application. We call it common emitter, because the emitter terminal is the common terminal between input and output. In this configuration, the base is input and the collector is output.

Application:-

It is used for as an amplification also same as common base configuration but, it is used in voltage amplification, current amplification, power amplification. Mostly it is used in current and power amplification. Therefore, this configuration is used the most.

Properties: -

1) The input impedance is the ratio of change in base emitter voltage (VBE) to change in base current when collector emitter voltage (VCE) is constant.

R_i= (ΔVBE / ΔIB)_VCE

2) The output impedance is the ratio of change in collector emitter voltage (VCE) to change in collector current when base current (IB) is constant.

Ro₌(ΔVCE / ΔIC)_IB

3) Its voltage gain is high.

4) Its current gain is high.

5) Its power gain is high.

5) It also has a current amplification factor, which we call β. β is known as the ratio of change in output current to change in input current.

β = ΔIC / ΔIB

Construction Diagram:-

As you know very well that for amplification we use transistor in active region. So we will understand the diagram of NPN and PNP transistor in active region very well. As shown in the diagram, the base terminal of transistor is connected to the one side of base resistance (RB). Other side of base resistance (RB) is connected to the positive terminal of VBB.

CE configuration of NPN

Negative terminal of VBB is directly connected to the ground terminal. Emitter of transistor is also connected to the ground terminal. Collector of transistor is connected to the one side of collector resistance (RC). Other side of collector resistance (RC) is connected to the positive terminal of VCC. Negative terminal of VCC is directly connected to the ground terminal.

CE configuration of PNP

Working:-

The base emitter of the transistor is forward bias junction which we call VBE. And its collector emitter of the transistor is reverse bias junction which we call VCE.

Expression:-

We had two equations in common base configuration.

IE = IB + IC ------------- (i)

IC = α.IE + I_CBO-------- (ii)

Put the value of IE from equation (i) in equation (ii)

IC = α.(IB + IC) + I_CBO

IC = α.IB + α.IC + I_CBO

IC - α.IC = α.IB + I_CBO

IC(1 - α) = α.IB + I_CBO

Dividing both side by (1 - α).

IC(1 - α) / (1 - α) = α.IB / (1 - α) + I_CBO / (1 - α)

IC = α.IB / (1 - α) + I_CBO / (1 - α) --------- (iii)

We know that

α = β / 1+β

Put the value of α in equation (iii)

IC = β / 1+β .IB / (1 - β / 1+β ) + I_CBO / (1 - β / 1+β)

IC = β / 1+β .IB / (1 - β + β / 1+β ) + I_CBO / (1 - β + β / 1+β)

IC = β / 1+β .IB / (1 / 1+β ) + I_CBO / (1 / 1+β)

IC = β / 1+β . (1+β / 1). IB + I_CBO .1+β / 1

IC = β. IB + I_CBO .(1+β)

We know that what is I_CBO.It is the leakage current for common base configuration. But in case of common emitter configuration, the leakage current is the combination of I_CBO .(1+β). We can say that

I_CBO .(1+β) = I_CEO

I_CEOis the leakage current of common emitter configuration. It is the current between collector and emitter terminal when base terminal of the transistor is open ie IB =0, So

IC = β. IB + I_CEO

This leakage current I_CEO we can neglect because it much smaller than IB

So IC = β. IB

β = IC / IB

:- β = Current amplification factor for common emitter

The value of β is lies between 20 to 500.

Input characteristics of common emitter configuration:-

Input characteristics of CE configuration

It is the curve between base current (IB) and voltage of base and emitter (VBE) at constant voltage of collector and emitter (VCE).

The first thing to do is to keep the VCE value constant. Then we have to increase the value of VBB gradually, as given in fig.

Input characteristics Chart of CE configuration

As we increase the value of VBB, the value of IB and VBE also increases with it. Similarly, by keeping the constant value of VCE three times or as you can do for many times than we get the reading of IB and VBE as shown in fig.

Output characteristics of common emitter configuration:-

Output characteristics of CE configuration

It is the curve between collector current (IC) and voltage of collector and emitter (VCE) at constant base current (IB). The first thing to do is to keep the value of IB constant. Then we have to increase the value of VCC slowly, as given in fig.

Output characteristics chart of CE configuration

As soon as we increase VCC, IC is gradually increase and IC much be larger than IB. The value of VCE also increase slowly. Similarly, by keeping the constant value of IE three times or as you can do for many times than we get the reading of IC and VCE as shown in fig.

Waveform:-

Its input waveform has a low signal and in its output waveform we get a high signal. But its input and output waveform invert each other.

Click to know about Common Base configuration

Common Base configuration of transistor, characteristics, application

2020-09-09T13:26:00.026+05:30

Common Base configuration of transistor, characteristics, application

Friends, today we will read about the common base configuration of BJT transistor. In this lecture, we will know its diagram, its characteristics and its application. We call it common base, because the base terminal is the common terminal for input and output. In this configuration, the emitter is input side and the collector is output.

Application:-

It is used for only as a voltage amplification. Signal in input is low and get high signal from output. It is mostly used in RF amplifier and high frequency also.

Properties: -

1) Its input impedance is very low.

R_{i =
ΔVBE / ΔIE}

2) Its output impedance is very high.

Ro_{=
ΔVCB / ΔIC}

3) Its voltage gain is high.We can say that, we got high voltage gain in the output.

4) Its current gain is unity. That is, we get output equal to input.

5) It also has a current amplification factor, which we call α. α is known as the ratio of output current to input current.

α = ΔIC / ΔIE

Construction Diagram:-

As you know very well that for amplification we use transistor in active region. So we will understand the diagram of NPN and PNP transistor in active region very well. As shown in the diagram, the emitter terminal of transistor is connected to the one side of emitter resistance (RE). Other side of emitter resistance (RE) is connected to the negative terminal of VEE.

CB configuration of NPN

Positive terminal of VEE is directly connected to the ground terminal. Base of Transistor is also connected to the ground terminal. Collector of transistor is connected to the one side of collector resistance (RC). Other side of collector resistance (RC) is connected to the positive terminal of VCC. Negative terminal of VCC is directly connected to the ground terminal.

CB configuration of PNP

Working:-

The base emitter of the transistor is the junction forward bias which we call VBE. And its collector base is a junction reverse bias which we call VCB. If we apply KCL then

IE = IB + IC

i) When part of emitter current reaches to the collector current is α.IE. We can say that IC = α.IE

ii) In reverse bias mode of collector base junction, leakage current is created due to movement of minority charge carrier.

IC = α.IE + I _leakage

We call this leakage current I_{CBO .} I_CBO means current between collector and base terminal when emitter terminal is open ie IE =0, So

IC = α.IE + I_CBO

Whatever I_CBO is in it, we can ignore it because IE is much greater than I_CBO

_SoIC = α.IE

α = IC / IE :- α = Current amplification factor

The value of α is always smaller than 1. Its value varies between 0.95 to 0.98.

Input characteristics of common base configuration:-

It is the curve between emitter current (IE) and voltage of base and emitter (VBE) at constant voltage of collector and base (VCB). The first thing to do is to keep the VCB value constant. Then we have to increase the value of VEE gradually, as given in fig.

Input characteristics of CB configuration

Chart of input characteristics of CB configuration

As we increase VEE, the value of IE and VBE also increases with it. Similarly, by keeping the constant value of VCB three times, we get the reading of IE and VBE as shown in fig.

Output characteristics of common base configuration:-

It is the curve between collector current (IC) and voltage of collector and base (VCB) at constant emitter current (IE). The first thing to do is to keep the value of IE constant. Then we have to increase the value of VCC slowly, as given in fig.

Output characteristics of CB configuration

Chart of output characteristics of CB configuration

As soon as we increase VCC, IC is smaller than IE till some reading and later becomes equal to IE. But the value of VCB changes slowly. Similarly, by keeping the constant value of IE three times, we get the reading of IC and VCB as shown in fig.

Waveform:-

Its input waveform has a low signal and in its output waveform we get a high signal.

Click to know about Common Emitter configuration

Definition of tissue, plant tissue, types and their function

2020-09-01T22:18:00.006+05:30

Definition of tissue, plant tissue, types and their function

Cell:

Before understanding Tissue we need to know about cell. Cell is the fundamental unit of life. Any living organism whether it is plant or animal, which is the smallest structure is called cell.

Tissue:

A group of cells which are similar in structure and function and having in common origin is known as tissue. This means that we cannot just call group of cells as tissue. We will just say tissue whose structure and function will be the same. The study of Tissue is called histology.

Importance of Tissue:

1) Tissue consists of multicellular organism. Multicellular organism means that the many cells perform the same function together. In the same way, their separate groups are formed and each group performs its own function, like one group performs the function of digestion and other group performs the function of respiration.

2) When each group performs different functions, then the workload of each cell is also reduced. This does not force the cell to perform any other function.

3) Helps create organization such as

Cell make tissue than tissue make organ than organ make organ system than after organ system make organism.

Basically tissues are of two types

1) Plant Tissue 2) Animal tissue

we will discuss only about plant tissue.

Plant tissue:

Plants are autotrophic organism. They prepare their food by process of photosynthesis. As we all know that plants are fixed. They do not move ahead except for a some unicellular algae.

They do not need much energy, therefore most of the tissues of plants are supportive that provide them a structural strength. Their organ and organ system have less complex structural organisation.

These are some tissues in plants that divide throughout their life. Tissues divided for the growth and reproduction of plants.We can say that such types of tissues are localised in certain regions.

Based on capacity of tissues, the various plant tissues can be classified as meristematic tissue and permanents tissue. Growth in plants is restricted to certain regions.

Classification of plant tissue:

1) Meristematic tissue:-

Cells are capable of cell division and have totipotency. Three types of meristematic tissues.

a) Apical meristem:-

Tips of root and stem.

b) Lateral meristem:-

Below bark, cambium, in dicot roots and stem.

c) Intercalary meristem:-

Inrenodes of stem

2) Permanent tissue:-

Mature cells incapable of cell division. They are of two types.

i) Simple permanent tissue:-

protective and supportive tissues composed of similar type of cells. They are of three types

a) Parenchyma b) Collenchyma c) Sclerenchyma

ii) Complex permanent tissue:-

Conductive tissues composed of more than one type of cells. They are of two types.

a) Xylem b) Phloem

CLICK HERE FOR:-

Protective tissue

What are the three types of Meristematic tissue?

2020-08-30T12:29:00.004+05:30

What are the three types of Meristematic tissue?

These tissues continuously form a number of new cells because they are totipotent i.e. can give rise to various cell types of the body. These tissues are plant tissues. Meristematic tissues have cells which are continuously dividing. Growth of their cell is limited to certain regions.

Characteristics of Meristematic Tissue:

1) These are found in the growing regions of the plant, e.g., shoot tip, root tip and cambium.

2) Its cells are immature and are capable of undergoing repeated division throughout their life.

3) These cells are spherical, oval, polygonal or rectangular in shape

4) Their cytoplasm in dense, cell wall is thin, nucleus is single and large, and vacuoles (single or free or no vacuoles), if present are smaller.

5) Intercellular space are lacking.

Classification of Meristematic Tissue:

According to their position on the plant body, they are of three types: a) Apical b) Lateral c) Intercalary.

a) Apical meristem:- It is found at the growing tips of stems (shoot) and roots. Its cells are roughly spherical, alike and divide continuously to make new cells. Thus, the root and stem of a plant grow in length (primary growth). In the cells of the apical meristem are typically small and nearly spherical. They have dense cytoplasm and relatively some small vacuoles.

b) Lateral meristem:- They are rectangular in shape and found on the lateral sides of roots and stems. These divide in tangential plane. Example is cork cambium and cambium of vascular bundles. These are cause thickening of stem and root.

c) Intercalary meristem:- It is a part of the apical meristem, which is separated from the apex during the growth. It is found at the base of the leaves or internodes (on either side of the node on twigs). They increase the length of the organ.

CLICK HERE FOR:-

Simple permanent tissue

Complex permanent tissue

Protective tissue

Protective tissue types and their function

2020-08-28T20:41:00.002+05:30

Protective tissue types and their function

Protective tissue:

As its name suggests, they act to protect tissue plants. They are present in the outermost layer of the tissue plant. They are usually of two types.
1) Epidermis 2) Cork(Phellem)

1) Epidermis:

Epidermis are present on the surface outside the plants. They act like as skin of the plant and form a protective layer in the plant. They are present in all parts of the plant such as leaves, stem, root.

shape and structure:

1) It is made of single layer of cell.

2) Their cells are elongated and flat.

3) It does not have intercellular space because its cells stick to each other so that they can protect the plant very well.

4) They are living.

Function:

1) The epidermis of dry habitat plants becomes thick so as to minimize the water losses in the plants.

2) Along with the deaf protection of the epidermis plants, the root creates long hair structure, due to which the root can absorb more nutrients and water.

3) The outer surface of epidermis has a wax layer of cutin called a cuticle. This layer protects plants from water losses, injury, fungal infection. These are not found in aquatic plants.

4) In Leaves the epidermis is absent at some place which we call stomata. Leading to gaseous exchange.

5) How much gaseous exchange is to happen and how much water vapor will go into the environment, they all decide the guard cell.

Stomata

2) Cork(Phellem):

When the plant grows, it changes from epidermis to cork. In other words, we can also say that when the plant is small, it has epidermis. As the plant starts growing, they get protection of cork. Cork is present in mature roots and shoots of plant.

shape and structure:

1) They have cell dead.

2) Their cells are compactly arranged.

3) They have no intercellular space.

4) Their wall have suberin

Function:

1) Protect the mature roots and shoots.

2) Cork releases a substance named suberin, which is water resistant (Water proof). It regulates gaseous exchange and water passage.

CLICK HERE FOR:-

Simple permanent tissue

Complex permanent tissue

Meristematic tissue

Complex permanent tissue types their functions and diagram

2020-08-28T20:19:00.002+05:30

Complex permanent tissue types their functions and diagram

Complex permanent tissue :

As its name suggests, the complex means more than one combination. They are made up of more than one type of cell. But when they meet together they perform the same function. The work of these type of tissue is to transport water, minerals and food from one place to another. These are two types.
1) Xylem tissue 2) Phloem tissue

1) Xylem:

These are a type of conducting tissue. Theirs work to transport water and minerals from root to other parts of the plant such as stem, leaves, flowers. Therefore, it is also called water vascular tissue. Its other name is also Hedrom. It gives strength to the plants.

These are four types.

a) Tracheids b) Vessels c) Xylem parenchyma d) Xylem sclerenchyma

a) Tracheids:

They are found parallel to the vertical axis of the plant. They are found in firm and gymnosperm.

shape and structure:

1) They are tube-like in view.

2) Their cells are elongated.

3) Their edges are tapped.

4) They are non living.

5) The cell wall is lignified.

6) Their walls are thick because they contain lignin.

7) They are unicellular.

Function:

They conduct water and minerals from roots to the leaves through pits.

b) Vessels:

shape and structure:

1) These are also tube-like in view.

2) In this we can place the cells one after the other.

3) They have lignified wall dead.

4) They are also non living.

5) Their edges are rounded or transverse.

Function:

They also conduct water and minerals from roots to the leaves like tracheids.

c) Xylem parenchyma:

shape and structure:

1) They are living.

2) Due to deposition of lignin therefore their cells walls are thin or thick.

Function:

1) It serves to store food.

2) Helps in convection of shore walls.

d) Xylem sclerenchyma:

shape and structure:

1) They have lignified wall dead.

2) They are non living.

Function:

Gives mechanical strength to the plant, which means that it supports the plant.

2) Phloem:

That is to say, in other words, these are also a type of conducting tissue. The work of phloem food produced by the photosynthesis process of transporting that food to different parts of the plants.

These are four types.
a) Sieve tubes b) Companion cells c) Phloem parenchyma d) phloem sclerenchyma

a) Sieve tubes:

shape and structure:

1) They are tube-like in view.

2)Their cell wall is thin.

3) In this we can place the cells one after the other.

4)Their end wall is porous, due to which its wall is like sieve which is also called sieve plate.

Function:

Transporting food produced by the leaves to the food storage organs of plants.

b) Companion cells:

shape and structure:

1) Their cell wall is thin.

2) They are elongated.

3) They are usually associated with lateral side of sieve tubes.

Function:

They are help in the transport of food along with the sieve tubes.

c) Phloem parenchyma:

shape and structure:

1)They are living.

2) They are intermingled with sieve tube.

Function:

Their main function is to store food and reach food to different parts of plants.

d) phloem sclerenchyma:

shape and structure:

1)Their cells are dead.

2) Their cell wall is thick.

3) They are elongated.

Function:

These provide mechanical strength to the plant. They are used for making ropes and rough cloth.

CLICK HERE FOR:-

Simple permanent tissue

Protective tissue

Meristematic tissue

Types of simple permanent tissue and their function

2020-08-28T19:40:00.002+05:30

Types of simple permanent tissue and their function

Types of simple permanent tissue

Simple permanent tissues:

As we know from their name, these tissues are very simple tissues. These tissues are formed only from a cell. They are made from such cells which are similar in structure, size and perform the same function. These are three types of tissues.

1) Parenchyma tissues

2) Collenchyma tissues

3) Sclerenchyma tissues

1) Parenchyma tissue:

It is present in every part of the plant, such as stem, root, leaf, flower etc.

Shape and structure:

1) Its cell wall is thin.

2) Its shape round is also polygon and elongated.

3) Due to its thin cell wall, it has a lot of intercellular space.

Functions:

1) It stores food inside the cell of the plants.

2) When parenchyma stores chlorophyll near us, we call it chlorenchyma.

3) Its cells become loosely packed, meaning that due to the increased intercellular space, there is a tissue present in it, which we call aerenchyma. Due to this, the plant stands easily in water.

2) Collenchyma tissue:

This tissue is found in the stems of plants and in the stalks of leaves.

Shape and structure:

1) Its cells are living.

2) There is cytoplasm inside their cell.

3) They are oval, polygon and elongated in shape.

4) They are very close to each other so that they have very little intercellular space.

4) Their cell walls are irregularly thickening in the wall, meaning they are thicker and thinner than elsewhere.

5) Their cell wall is made of cellulose.

6) Vacuoles are present inside them.

Functions:

1) It is a mechanical tissue.

2) It provides mechanical strength to the leaves of the plant.

3) It also provides flexibility to the plant.

4) It allows bending in tendrils and stem.

3) Sclerenchyma tissue:

It is present in the stem around the vascular bundles. They are also found in veins of leaves. It is also present in the hard cover of a seed. Such as a nut or almond cover.

Shape and structure:

1) Long and narrow in shape.

2) Their cell wall is made of lignin.

3) Their cell wall thickness is uniform.

4) Cavity inside them ends due to their cell wall being thick.

5) Their cells are completely dead.

6) There is absolutely no intercellular space inside them.

Functions:

1) These tissues provide mechanical strength to the plant cell.

2) These tissues provide protection to the plant cell.

CLICK HERE FOR:-

Complex permanent tissues

Protective tissue

Meristematic tissue

Function of blood, their types and blood deficiency diseases

2020-08-28T19:12:00.001+05:30

Function of blood, their types and blood deficiency diseases

Blood is a fluid connective tissue. It is salty in taste and slightly alkaline in nature. The pH value of blood is 7.4. The color of blood is also different in different castes of different beings.

In human beings, it forms 7–10% of the body weight. Normally, the amount of blood in men is 5–6 liters and the amount of blood in women is half liters less than that of men.

Function of blood:

It is straw- colored fluid, and makes up about 55% of the total blood volume in our body. Plasma is a complex fluid and includes in it organic salts and organic compounds. Organic substances of plasma are soluble.

Plasma contains 90% water content and 10% other substances such as Proteins, glucose, amino acids, lipids, vitamins, enzymes and hormones. The work of plasma in our body is supply of blood to all cells of the body and The waste materials (urea, uric acid) are transported to kidneys for excretion. There are three types of proteins in it.

· Albumins :- Protein called albumin is found in maximum amount in plasma. This type of protein maintain the pressure of blood in our body.

· Globulin :- Globulin acts as a protective watch in our body, this means that it works to protect our body from diseases.

· Fibrinogen :- If we talk about fibrinogen protein then it plays a very important role in our body. This is to prevents blood from flowing through our body’s wound, that is, it is used to make a blood clot in our body. If fibrinogen protein is separated from the plasma, the remaining part is called serum.

45% of blood cells are found in our blood. There are three types of these.

· Red Blood Cells (RBCs) or erythrocytes

· White Blood Cells (WBCs) or leucocytes

· Platelets or thrombocytes

To know about blood cell briefly Click here

Blood deficiency is a disease called anemia. Lack of blood means that our body is deficient in iron, hemoglobin and vitamin B-12.

To make up for the lack of blood, we should take the following measures.

· Low carbohydrate food should be eaten.
· Should drink more and more water.
· We should eat food that contains high amounts of vitamin B-12, such as milk products, meet, eggs, fortified breakfast cereals (oats), nutritional yeast products.
· If we talk about vegetables, we should eat green leafy vegetables so that there is no lack of iron in our body.
· We should eat dried fruits and beans.

How to Use VLOOKUP function (VLOOKUP formula) in Excel

2020-08-28T18:54:00.003+05:30

How to Use VLOOKUP function (VLOOKUP formula) in Excel

Friends, today we will understand in detail about a formula of MS Excel which is known as VLOOKUP.

We use this formula called VLOOKUP where there are too many workers in a factory or too many children in a school. We have to get information about one of the many workers or about one of the many children. Meaning that we have collected as much information of a worker or any child inside our computer. VLOOKUP will tell us all that information very easily.

VLOOKUP style:

=VLOOKUP(lookup_value, table_array, col_index_num, [range_lookup]).

1. lookup_value:- lookup_value means in relation to which value we have to check our data.

2. table_array:-In table_array we will select the table array (one column to another column) as far as the data we want.

3. col_index_num:- col_index_num means what column number data we have to take.

4. range_lookup:-In range_lookup we have to select False or True. False means exact match and True means approximate match (default setting). You can also ignore range_lookup if you want. But instead of ignoring it, we use False for exact matching of our data.

For this we take an example. Suppose we have a list of students. In this list, roll numbers of students, names of students, in which subject of a student are how many numbers and how many marks they have secured out of total marks etc. As you can see in Fig 1.

Fig 1

Now as if I want to know what is the name of the student of roll number 5 and in addition to this, whatever information we have collected about roll number 5 inside our computer, we get all the information immediately. So for this we will put VLOOKUP formula in this list.

How to apply VLOOKUP formula:

As you can see in Fig 2(a), Fig 2(b), whatever data is in row 1 such as student name, gender, math, science, english, gk and marks etc. We have to copy and paste all the data in the same page in a separate box of any excel, as given in the image.

Fig 2(a)

First of all we will put VLOOKUP formula on student name. We will write that = VLOOKUP (A16, A2: B10,2, FALSE). A16 in it means lookup value. Now we have to check our data with respect to this lookup value. Meaning that I have to put any roll number in this column of A16. A2: B10 means that we have to select the name of the student of the column from column A2 to B10.

Fig 2(b)

This means that we can say that whichever student's roll number we enter, we can see the name of that student. “2” means the column of student name is another. FALSE tells our data with exact match. Similarly, we will create a statement according to this formula in all our columns. Such as:

Gender : =VLOOKUP(A16,A2:C10,3,FALSE)
Math : =VLOOKUP(A16,A2:D10,4,FALSE)
English : =VLOOKUP(A16,A2:E10,5,FALSE)
History : =VLOOKUP(A16,A2:F10,6,FALSE)
Science : =VLOOKUP(A16,A2:G10,7,FALSE)
GK : =VLOOKUP(A16,A2:H10,8,FALSE)
Marks Obtained : =VLOOKUP(A16,A2:I10,9,FALSE)
Total marks : =VLOOKUP(A16,A2:J10,10,FALSE)

With the help of this formula, we have got all the information about roll number 5. With the help of this formula, we can get information about any roll number.

If you want to know about Count function then clickhere

How to make automatic street light using LDR circuit

2020-08-28T18:29:00.000+05:30

How to make automatic street light using LDR circuit

Friends, today we will design the automatic street light circuit, which is made with the help of LDR, BC 547 transistor and relay. With the help of this circuit, we can get the main (220V) led bulb automatic ON and OFF. Some components are required to make this circuit. Those components are something like this.

1. LDR ----------------------------1pc

2. BC547 -------------------------1pc

3. Resistance 10KΩ -----------1pc

4. Led bulb 220V ---------------1pc

5. Battery 9VDC ----------------1pc

6. Relay 9VDC ------------------1pc

7. General PCB------------------1pc

8. Connecting wires

Before making this circuit, it is very important to know some important components. Because the circuit we make, we must first know about the components inside it, what are they doing in our circuit.

1) LDR

As its name suggests, it is a kind of resistor, which depends on the light. As the light decreases or increases, its resistance decreases and increases. Its resistance increases very much when it is dark light. Due to which current flow is not possible. Its resistance decreases when it is bright light. Due to which current flows easily.

2) BC547(Bipolar Junction Transistor)

As its name itself suggests, it has 2 junction (N junction and P junction). This transistor consists of 3 terminals (Base, Collector, Emitter). It is an NPN transistor. When positive supply provide to the base of the transistor, due to which the transistor works in ON condition. The direction of current of NPN transistor is emitter from collector. Transistor is current control device.

3) Resistance

Resistance is a property of conductor that prevents the current flowing in the circuit. The unit of the resistance is OHM (Ω).

Now we make the automatic street light circuit.

Working

Diagram construction

As shown in Fig 1, the positive terminal of the battery is connected to a terminal of resistance R1 and cathode terminal of diode D1 and relay coil terminal 1 and the negative terminal of the battery is directly connected to the ground.

The second terminal of Resistance R1 is connected to the base terminal of transistor BC547 (Q2) and terminal 1 of LDR1. Terminal 2 of the LDR1 is directly connected to the ground. The anode terminal of diode D1 is connected to the collector terminal of transistor BC547 (Q2) and relay coil terminal 2. The emitter terminal of the Transistor BC547 (Q2) is directly connected to the ground.

Working

As you can see in Fig 1, If it's night time there is no light on the LDR. This means that the resistance of LDR is high and there is no current flowing in the LDR.

Fig 1

The transistor BC547 (Q2) will turn ON due to the positive resistance of the battery coming from the positive terminal to voltage resistance R1and the transistor BC547 (Q2) getting a positive supply from resistance R1. Due to turn ON the transistor BC547 (Q2) collector and emitter terminal short and ground terminal will connect to the relay coil terminal 2.

As soon as the relay coil terminal 2 gets ground, the relay will become ON. As soon as the relay is ON, the common point of the relay will connect with the normally open(NO) and the main supply will be ON which will cause our lamp to burn. Now our lamp will keep burning at night.

As you can see in Fig 2, as soon as morning comes the light comes on the LDR, the resistance of the LDR will decrease and current flow will start from it. Due to the low resistance in the LDR, the base terminal of the transistor BC547 (Q2) will get ground supply and the transistor BC547 (Q2) will be OFF.

Fig 2

So that contact between collector and emitter terminal of transistor BC547 (Q2) will be lost. Now due to lack of ground of relay coil terminal 2, the relay will be OFF. As soon as the relay is OFF, the common point of the relay will connect with the normally close(NC) and the main supply will be OFF so that our lamp will be OFF. Now our lamp will remain OFF during the day. Then in the evening the lamp will go automatic ON and in the morning the lamp will go off automatically. We can take a preset of 100KΩ instead of 10K in resistance R1 to get the lamp turned ON-OFF quickly.

How to find out battery backup time

2020-08-28T18:15:00.003+05:30

How to find out battery backup time

Friends, today we will tell you how to find out the backup time of inverter battery. There are two ways to extract battery backup time. Today I will tell you both these methods and then later we will extract the battery backup time of the bulb with the help of a numerical.

First way-->

We considered that:

Inverter load = 300W

Battery voltage = 12V

Battery current rating = 150AH

Step 1 :- First of all we should know their discharging current. Discharging current means how much current was used to discharge the battery 100%. so :-

Discharging current = Inverter load / Battery voltage

Discharging current = 300W / 12 v

Discharging current = 25A

Step 2 :- After found the discharging current., now we have to know how many hours it will take to charge the battery 100%. so :-

Battery hours for 100% charging = Battery in AH / Discharging current

Battery hours for 100% charging = 150AH / 25A

Battery hours for 100% charging = 6 hrs

That is, it will take 6 hours for our battery to be fully charged. But according to thumbrull we always go by counting 80% discharging time.

Backup hours for 80% charging = 6 X 80%

Backup hours for 80%charging = 6 X 80 /100

Backup hours for 80% charging = 4.8 hrs = 4hr 48min

That is, the battery back up time of 300W inverter load is 4hr 48min. This means that if the load of our inverter is 300W then our battery will run last 4 hours and 48 minutes.

Second way-->

We considered that:

Inverter load = 300W

Battery voltage = 12V

Battery current rating = 150AH

Total battery backup time calculation = battery current rating X battery voltage X number of batteries X efficiency of battery / total inverter load in watt

: - We will always count the efficiency of the battery to 80% so ----

Total battery backup time calculation = 150AH X 12V X 1 X 0.8 / 300W

Total battery backup time calculation = 4.8 hrs = 4hr 48min

That is, the battery back up time of 300W inverter load is 4hr 48min. This means that if the load of our inverter is 300W then our battery will run last 4 hours and 48 minutes.

Numerical--->

We have a battery with a voltage of 12V and a current rating of 150AH, and if we are lighting a 100W bulb with this battery, how long will our 100W bulb burn.

Solution-- According to the question:-

Bulb load = 100W

Battery voltage = 12V

Battery current rating = 150AH

Total battery backup time calculation = battery current rating X battery voltage X number of batteries X efficiency of battery / total inverter load in watt

: - We will always count the efficiency of the battery to 80% so ----

Total battery backup time calculation = 150AH X 12V X 1 X 0.8 / 100W

Total battery backup time calculation = 14.4 hrs = 14hr 24min

So on a 150AH battery our one 100W bulb will burn for about 14 hours 24 minutes.

LDR circuit using BC547 bipolar junction transistor

2020-08-28T18:08:00.000+05:30

LDR circuit using BC547 bipolar junction transistor

Friends, today we will design the LDR circuit, which is made with the help of LDR and BC 547 transistor. With the help of this circuit, we can get the LED automatic ON and OFF. Some components are required to make this circuit. Those components are something like this.

1. LDR --------------------------- 1pc

2. BC547 -------------------------1pc

3. Resistance 22KΩ ------------1pc

4. Resistance 330Ω -------------1pc

5. Led 5mm any colour --------1pc

6. Battery 9VDC ----------------1pc

7. Connecting wires

Before making this circuit, it is very important to know some important components. Because the circuit we make, we must first know about the components inside it, what are they doing in our circuit.

1) LDR

2) BC547(Bipolar Junction Transistor)

3) Resistance

Resistance is a property of conductor that prevents the current flowing in the circuit. The unit of resistance is OHM (Ω).

Now we make the LDR circuit.

Working

Its working can be done in two ways.

1) If we want the led to be ON at night and led off by day.

2) If we want the led to be ON during the day and led off at night.

So, I will tell you both these ways how we make the circuit according to their working.

1) LED ON in darkness and OFF in brightness

Diagram construction

As shown in Fig 1, the positive terminal of the battery is connected to a terminal of resistance R1 and resistance R2 and the negative terminal of the battery is directly connected to the ground. The second terminal of Resistance R1 is connected to the base of transistor BC547 (Q2) and terminal 1 of LDR. Terminal 2 of the LDR is directly connected to the ground. The second terminal of Resistance R2 is connected to the anode of the led. Led's cathode is connected to the collector of transistor BC547 (Q2). The emitter of the Transistor BC547 (Q2) is directly connected to the ground.

Fig 1

Working

As you can see in Fig 1 (a) and Fig 1 (b), there is no light in the LDR yet. This means that the resistance of LDR is high and none of it is running current. The transistor BC547 (Q2) will turn ON due to the positive resistance of the battery coming from the positive terminal to voltage resistance R1 and resistance R2 and the transistor BC547 (Q2) getting a positive supply from resistance R1.Our LED will also turn ON as the Transistor BC547 (Q2) becomes ON.

Fig 1(a)

Fig 1(b)

As soon as the light comes in the LDR, the resistance of the LDR will decrease and current flow will start from it. Due to the low resistance in the LDR, the base terminal of the transistor BC547 (Q2) will get ground supply and the transistor BC547 (Q2) will be OFF. Our LED will also be OFF as the Transistor BC547 (Q2) is OFF.

2) LED ON in brightness and OFF in darkness

Diagram construction

As shown in Fig 2, the positive terminal resistance of the battery is connected to terminal 1 of R4 and LDR2 and the negative terminal of the battery is directly connected to ground. Terminal 2 of LDR2 is connected to the base of transistor BC547 (Q2) and terminal 1 of resistance R3. Terminal 2 of Resistance R3 is directly connected to the ground. The second terminal of Resistance R4 is connected to the anode of the led. Led's cathode is connected to the collector of transistor BC547 (Q2). The emitter of the Transistor BC547 (Q2) is directly connected to the ground.

Fig 2

Working

As you can see in Fig 2 (a) and Fig 2 (b), there is no light in the LDR yet. This means that the resistance of LDR is high and none of it is running current. Due to no current flow, the transistor BC547 (Q2) will not receive any positive supply and our transistor BC547 (Q2) will remain OFF. Our LED will also remain OFF as the Transistor BC547 (Q2) is OFF.

Fig 2(a)

Fig 2(b)

As soon as the light comes in the LDR, the resistance of the LDR will decrease and current flow will start from it. Due to current flow in LDR, the base terminal of transistor BC547 (Q2) will get positive supply and transistor BC547 (Q2) will become ON. Our LED will also turn ON as the Transistor BC547 (Q2) becomes ON.

Types of blood cells and their functions and images

2020-08-28T17:49:00.002+05:30

Types of blood cells and their functions and images

Blood cells types

45% of blood cells are found in blood. It is of three types:

(i) Red Blood Cells (RBCs) or erythrocytes (ii) White Blood Cells (WBCs) or leucocytes (iii) Platelets or thrombocytes

Blood cells

(i) Red Blood Cells (RBC)

The unique feature of RBCs is the presence of a red, oxygen-carrying pigment, the hemoglobin, In their cytoplasm. The shape and size of RBCs vary in different animals.

The cells may be uninucleated or non-nucleated. In almost all the vertebrates, except mammals, these are nucleated, oval and biconvex. In mammals, these are non-nucleated, biconcave and circular.

Actually, the nucleus is present in the RBCs of mammals initially but when these cells are finally differentiated and mature, the nucleus, mitochondria and endoplasmic reticulum are degenerated.

If we talk about human body, the amount of RBC in blood cells is 90%. Its life is 120 days. RBCs are born in the human body in the bone marrow and die in Spleen. Spleen is also known as RBC cemetery. The function of RBC is to conduct oxygen and carbon dioxide.

RBC deficiency diseases

Anemia, jaundice etc.

(ii) White Blood Cells (WBCs)

These are colourless, nucleated and motile (amoeboid) cells of blood, much larger than RBCs, but less in number. All leucocytes are capable of amoeboid movement. These are of two main kinds; phagocytes and immunocytes.

Phagocytes are capable of phagocytosis and they carry out the function of body defense by engulfing bacteria and other foreign substances.

If we talk about the human body, the amount of WBC in blood cells is the lowest. It has a life of 3-4 days. The WBC is born in the human body in the bone marrow and dies in blood.

Vitamin A increases WBC in blood. The decrease in the amount of WBC is called Leukopenia. Excess of WBC is called Leukemia. WBC is of three types:

(a) Granulocytes:

They have irregular shaped nuclei and cytoplasmic granules with specific staining properties. They include eosinophils, basophils and neutrophils.

(b) Agranulocytes:

These are non-granular leucocytes, having a roughly round or indented nucleus and clear cytoplasm. They include monocytes. They ultimately migrate to body tissue and transform into macrophages and histocytes.

(c) Immunocytes:

They produce antibodies and are involved in immune response. They include lymphocytes that contain central, spherical nucleus and a little cytoplasm with no granules and produce antibodies.

WBC deficiency diseases

Blood cancer etc.

(iii) Blood platelets or thrombocytes:

These are minute, highly contractile, round or oval, biconvex discs with granular cytoplasm, but without nucleus. As is recently discovered, the platelets are fragments which form as buds and pinch off from certain large cells (megakaryocytes) in bone marrow. They help in the clotting of blood in the site of injury to a blood vessel, so as to prevent further loss of blood.

Platelet deficiency diseases

Chikungunya, Dengue etc.

Occurrence

It occurs in blood vessels called arteries, vanes and capillaries that are connected together to form the circulatory system. The highly branching network of vessels enables blood to reach every part of the body.

Blood cells function

Ø It transports oxygen from respiratory organs to various body tissues.

Ø It carries carbon dioxide from body tissues to respiratory surfaces like lungs, skin, etc.

Ø Digested food absorbed from the intestine is carried to different parts of the body.

Ø It carries excretory wastes produced in the body to kidneys for elimination.

Ø It maintains the body temperature.

COUNT, COUNTA, COUNTIF, COUNTIFS functions in MS excel

2020-08-28T15:51:00.004+05:30

COUNT, COUNTA, COUNTIF, COUNTIFS functions in MS excel

COUNT

The COUNT function is only used to count numeric value (Numbers only). It does not count the alphabetical value. Suppose if we want to count marks of one subject of some students, then we can count easily. It will be known how many students are total. To use this function The formula for is as follows.

COUNT (value1, value2 ............)

Fig 2(a)

Fig 2(b)

You can see this example in Fig 2(a) and Fig 2(b). In this Fig, the color you see in the "value" of the COUNT (value1, value2 ......) function, you will also see the same color line in Fig. This will make it easier for you to understand it. In the same way, you can understand this function by taking another example as well.

COUNTA

The COUNTA function is only used to count alphabetical. It does not count the numeric value (Numbers only). Suppose there are some students in our class but we do not know how many students are there. So we can count students with the help of COUNTA function. The formula for using this function is as follows.

COUNTA (value1, value2 ...............)

Fig 3(a)

Fig 3(b)

You can see this example in Fig. 3(a), Fig. 3(b). In this Fig, the line of the same color you see in the "value" of the COUNTA (value1, value2 ......) function, you will also see the same color in Fig. This will make it easier for you to understand it. In the same way you can understand this function by taking another example as well.

COUNTIF

Now we will know how to use the COUNTIF function where the COUNTIF function is used. The COUNTIF function is used where any information about a person or one thing is to be taken. So we can say this function will only work on one condition.

Suppose we want to know how many days a student was present from Monday to Saturday and how many days were absent. So with the help of this function, we can also find out the attendance of every student. We can also remove it according to the days and can be removed according to the months and years. The formula for using this function is as follows.

COUNTIF (range, criteria ...........)

Fig 4(a)

Fig 4(b)

Fig 4(c)

You can see this example in Fig. 4(a), Fig. 4(b), Fig. 4(c). In this Fig, the color you see in the "range" or "criteria" of the COUNTA (range, criteria ......) function, the line of the same color you see in Fig. Will be. This will make it easier for you to understand it. In the same way, you can understand this function by taking another example as well.

COUNTIFS

Now we will know how to use the COUNTIFS function where the COUNTIFS function is used. The COUNTIFS function is used where more than one condition is working. Suppose we want to know how many boys or how many girls in our class have got more than 65 marks in any subject. In this way we can also know how many boys over 65 or more How many girls have got their marks. The formula for using this function is as follows.

COUNTIFS(criteria_range1, criteria1, [criteria_range2, criteria2] .............)

Fig. 5(a)

Fig. 5(b)

Fig. 5(c)

You can see this example in Fig. 5(a), Fig. 5(b), Fig. 5(c). In this Fig, the line of the same color you see in the "range" or "criteria" of the COUNTA (criteria_range1, criteria1, [criteria_range2, criteria2] ......) function. You will see in Fig. This will make it easier for you to understand it. In the same way, you can understand this function by taking another example as well.

When safety fuse is worked in a circuit?

2020-08-28T15:19:00.000+05:30

When safety fuse is worked in a circuit?

Fuse

Fuse is an electrical safety device that protects our circuit from over current, making our circuit safe.

How does Safety fuse circuit work

I will tell you how the fuse works. See what happens in it that we select our fuse according to the current that our circuit needs to work. Just like an external current is exceeded from our fuse current rating then our fuse gets burnt in that case which prevents our circuit from malfunctioning. In fact, the function of fuse is that in case of over current or short circuit, burning itself protects our internal circuit. Hence we also call it safety fuse.

Fuse symbol

How to choose Fuse

To find out how much Amp will be used in our instrument, we have to keep some things in mind. For the instrument in which we have to pu the fuse, we should know its primary voltage, secondary voltage and current. We will find out the primary current from it and then we will find the current rating of fuse.

Vp = Primary voltage

Vs = Secondary voltage

Ip = Primary current

Is = Secondary current

Vp/Vs = Is/Ip

इसी तरह से-->

Ip = Vs X Is / Vp

Fuse rating = Ip X 1.25

For example==> Vs = 22V , Is = 2.5A , Vp = 220V then calculate the fuse rating.

Sol----- Ip = Vs X Is / Vp

Ip = 22 X 2.5 / 220

Ip = 0.25A(250mA)

Fuse rating = Ip X 1.25

Fuse rating = 250 X 1.25

Fuse rating = 312.5 ≈ 300mA

So our 2.5 A instrument will have a fuse of 300mA, which will protect our instrument from over current or short circuit.

What material is fuse made of

Inside the fuse is a wire strip which is made of tin, lead, zinc, copper, silver metal. They have some special properties, so they are used as fuse wire. These properties are something like this.

1) Their melting point is less.

2) They have low ohmic loss.

3) Their conductivity is high.

4) Due to conductivity high, their resistivity is low.

5) Their cost is low.

The fuse is designed in such a way that it can melt easily in case of over load or short circuit. The thickness of the wire of the fuse varies and depends on how much current we have to flow into the fuse. The current rating of fuse also varies according to the different current. Usually we use fuse of material made from lead and tin as their melting point is low.

Chute conveyor(Trough conveyor features and application)

2020-08-28T15:10:00.005+05:30

Chute conveyor (Trough conveyor features and application)

Conveyor chute (Trough conveyor)

Conveyor chute or Trough conveyor is a mechanical device that transports material or bags with the help of gravity. We use Trough conveyors for scrap and bag handling etc.

Types of conveyor chute

According to the needs of application conveyor chute are of different types.

1) Straight / Inclined 2) Spiral / Curved

1) Straight/Inclined chute

Straight / Inclined chute is planted where there is a lot of space in the plants. They are simple in design. Mostly they are flat. We can keep them within 8 to 10 degrees so that the handling material can flow easily. Their surfaces are always smooth. As far as possible they should be made with a single plate so that there is no damage to the handling material. It has a skirt board on both sides. It should be fitted with a small rod on either side of the skirt board and flat plate so that there is no damage.

2) Spiral/Curved chute

Spiral / Curved chutes are very complicated in design but they required very less space as compare to Straight / Inclined. We can keep them within 8 to 10 degrees so that the handling material can flow easily. We should design their profile very carefully because the skirt board in it is made by bending the plate on which the material flows. The skirt board is also folded at a particular angle. In the Spiral / Curved chute, a small profile is weld around a hollow vertical rod. We fix the vertical rod with the ground. We grind the welding part with the help of a grinder. In this we place a small rod at the ends of the plate, so that there is no problem in the handling material.

Features

1) Conveyor chute surface should be smooth.

2) There should be very less dynamic friction.

3) This conveying system is much less expensive than any other conveying system, as they are operated with gravity and do not require any external power.

Application

1) We use this chute to move the material from one floor to another floor.

2) We use these types of chutes are in cement, lime and gypsum industries.

3) We use these types of chutes are also in food industries.

4) We use these types of chutes are also in pharmaceutical industries.

Cement Grinding Plant Process

Series and Parallel combination of Resistance

2020-08-28T14:56:00.003+05:30

Series and Parallel combination of Resistance

When the resistor is connected in series to any circuit, the resistance of the circuit increases. I would like you to understand this whole process in detail. Friends, these combinations are actually 2 types.

1) Series combination 2) Parallel combination

1) Series combination

When resistance is connected in series, the value of resistance increases. Which increases the equivalent resistance of the circuit. How will it be known whether resistance is in series or not. Friends, always remember that if there is resistance series, the voltage will always be different and the current will always be the same.

Resistance in series

The formula for Equivalent resistance in Series combination is like this

R = R1 + R2 + R3

Now how and where did it come from. Some mathematical proof of it is like this.

We can say that…

V = V1 + V2 + V3 ---------- (1)

According to Ohm's Law ---->

V = I R

So this is the Series combination, in this the current will always be the same but the voltage will always be different. So we will keep the value of V of Ohm's Law in eq (1).

V = V1 + V2 + V3

I R = IR1 + IR2 + IR3

IR = I (R1 + R2 + R3)

R = R1 + R2 + R3

R = Equivalent resistance

Numerical----

Q = If R1 = 6Ω, R2 = 4Ω. If these resistance in connected in series, then calculate its equivalent resistance?

Solution=> R=Equivalent resistance

R = R1 + R2

R = 6Ω + 4Ω

R = 10Ω

2) Parallel combination

When resistance is connected in parallel, the value of resistance decreases. Which reduces the equivalent resistance of the circuit. How to know whether resistance is in parallel or not. Friends, always remember that if there is resistance series, the voltage will always be the same and the current will always be different.

Resistance in parallel

The formula for equivalent resistance in parallel combination is like this

R = 1 / R1 + 1 / R2 + 1 / R3

Now how and where did it come from. Some mathematical proof of it is like this.

We can say that…

I = I1 + I2 + I3 ---------- (1)

According to Ohm's Law ---->

V = I R

I = V / R

So this is a parallel combination, in this the current will always be different but the voltage will always be the same. So we will keep the value of I of Ohm's Law in eq (1).

I = I1 + I2 + I3

V / R = V / R1 + V / R2 + V / R3

V / R = V (1 / R1 + 1 / R2 + 1 / R3)

R = 1 / R1 + 1 / R2 + 1 / R3

R = Equivalent resistance

Numerical----

Q = If R1 = 10Ω, R2 = 10Ω. If these resistance in connected in parallel, then calculate its equivalent resistance?

Solution=> R=Equivalent resistance

R = 1/R1 + 1/R2

R = 1/10Ω + 1/10Ω

R = 5Ω

DPC (Deep Pan Conveyor) OR Clinker Conveyor

2020-08-28T14:32:00.009+05:30

DPC (Deep Pan Conveyor) OR Clinker Conveyor

DPC is used to convey the clinker from the grate cooler to blending silo.

For clinker transportation shaker troughs or vibrating chutes with high frequency oscillation amplitude were used. However, these troughs or chutes could be used only for horizontal transportation of clinker. For vertical transportation it was necessary to transfer the clinker into bucket elevators or into swing bucket conveyors.

DPC to Blending silo

These clinker conveying machines developed much dust not only during horizontal transportation, but also during transloading in vertical conveyors. These drawbacks motivated the cement machinery manufacturers to develop new-styled transportation arrangements, so-called bucket apron conveyors, which are able to convey the clinker not only horizontally but also on inclinations (mostly 40-45 c, in exceptional cases even up to 60 °) almost without generation of dust.

When planning a clinker conveying installation, a filling level of 75— 80'% should be considered, When locating the steel cell conveyor directly underneath the clinker cooler, the conveying capacity should correspond to the normal kiln capacity at a 40-- 50 % cell filling level to prevent overfilling in case of possible kiln ring breakage, However, drive capacity should be set as for 100 % cell filling level. Further, it is important that capacity reduction factors are applied when considering inclined conveyors as compared to horizontal conveyors, Spillage is minimized by steep inclines or when the pans articulate over the head or tail shafts. This type of conveyor is ideally suited for handling hot clinker in the cement plants or for conveying materials from fines to 150 mm lump size.

Features

v Good for conveying of clinker with a high content of fines

v Minimum spillage

Benefits

Efficient and reliable operation

Suits applications with limited space

Low operating costs

Minimum and easy maintenance

Outstanding service life

Chute from DPC (Deep Pan Conveyor) to Bucket elevator

DPC convey the clinker into the bucket elevator through the chute. This chute should be designed with care so that there should not chocking problem occur. It is necessary that one end of the chute covers the whole DPC head end so that no spillage of clinker. Another end of the chute should cover the bucket elevator inlet. It also take care chute should be with proper angle. Angle of chute should be greater than 45 degree. Chute should be with lining of wear plate so that wearing strength of chute increased. If possible there should be small door in chute in maintenance purpose so that we can see the problem easily if occur.

To know about cement grinding plant click here

AC TO DC CONVERTER CIRCUIT

2020-08-28T14:24:00.003+05:30

AC TO DC CONVERTER CIRCUIT

We also call AC TO DC converter as rectifier. Through rectifier we can convert AC to DC. Suppose we have to convert from 9VAC to 5VDC. In its circuit diagram you can see how many components are used in it. We see them one by one.

TRANSFORMER

First of all we have to take a step down transformer, which has an input voltage of 230VAC. It depends on you which input voltage you want to work on. I have assumed the input voltage230VAC here, which is the primary winding of the transformer. In the secondary winding of the transformer we will place 9VAC (RMS value). If we talk about the peak value of the secondary winding of the transformer, then 14VAC will be approx.

BRIDGE RECTIFIER

Then we will use Rectifier to convert AC to DC. Rectifier circuits such as Half wave, Full wave are also there. But most often a Bridge Rectifier is used to convert AC to DC. It forms a bridge consisting of 4 diode hence it is called Bridge Rectifier. Diode D2 and D4 conduct in the positive half cycle and Diode D1 and D3 conduct in the negative half cycle. Then our DC voltage changes to AC voltage. But the DC voltage that we get after rectifier is found as pulse. We call this pulsating DC. But if seen, she is not a smooth DC in the proper way. That is, some ripples come in it. Use the capacitor to remove such ripples.

CAPACITOR

Capacitor is used in our circuit for filtering and removing ripples. I tell you how much voltage the capacitor should have. Suppose the circuit has 12 volt after the rectifier, then the voltage of our capacitor should be 30V (12X2 = 24, 24 + 6 = 30). We must have a capacitor of 30V Have to be installed. A 470uF / 30V capacitor would be best for this. The DC voltage will improve after installing this capacitor.

VOLTAGE REGULATOR

If we need 5VDC in the output we will take a 7805 voltage regulator. The 7805 voltage regulator gives us 5VDC at the output. If we check the datasheet of 7805 voltage regulator then its maximum input voltage is 25V and its maximum current rating is 1.5A. According to our circuit, we can easily use this voltage regulator. So in this way we will create 5VDC. Friends, after this we have to put a small capacitor in its output so that our voltage becomes a pure DC voltage. Friends, the capacitor we will install will be installed keeping our output in mind. Now our output voltage is 5VDC and then the voltage of our Capacitor should be 15V (5 X 2 = 10, 10 + 3 = 13). A 100uF / 15V capacitor would be best for this. So this is how the AC TO DC converter became.

Two electric lamps are rated as 200 V 100w and 220v 40w respectively. Calculate electrical resistance

2020-08-28T14:18:00.006+05:30

Two electric lamps are rated as 200 V 100w and 220v 40w respectively. Calculate electrical resistance

Well, we can solve this question in two ways. That is, we can calculate resistance in two ways. I am going to tell you both these ways. Let me first mention the symbols here.

P = Power

V = Voltage

I = Current

R = Resistance

Ok guys Now we move forward.

First Way ==>

(A) Voltage of first lamp (V) = 200 V

Power of first lamp (P) = 100 W

As we all know that ====>

power = voltage x current (P = V X I) ----------- (EQ 1)

To find out the resistance of the lamp, we must first know how much the current of this lamp is. If we know the current of the lamp, then we can easily find the resistance of this lamp.

Because according to Ohm's Law we have to do this. I will tell you in this question what is the interpretation of Ohm's Law. So we take EQ 1.

P = V X I

So in this way we can say that

I = P / V ---------------------- (EQ 2)

We have given values of P and V, we have to put this value in EQ 2.

I = 100/200

I = 0.5 A

Now we have come to know the current of this lamp. Now we will remove the resistance by applying the formula of Ohm's Law. But before that you should know what is Ohm's Law. Let me tell you a very simple explanation of Ohm's Law, you will never forget it in life. The electric current of any circuit is always directly proportional to its voltage and inversely proportional to its resistance. Now we will calculate the resistance by applying Ohm's Law formula.

According to Ohm's Law ---->

V = I R

R = V / I

= 200 / 0.5

R = 400 Ω

(B) Voltage (V) of the second lamp = 220 V

Power of second lamp (P) = 40 W

As we all know that ====>

power = voltage x current (P = V X I) ----------- (EQ 1)

So in this way we can say that

I = P / V ---------------------- (EQ 2)

We have given values of P and V, we have to put this value in EQ 2.

I = 40/220

I = 0.181 A

Now we will also take the value of resistance by applying the formula of Ohm's Law.

According to Ohm's Law ---->

V = I R

R = V / I

= 220 / 0.181

R = 1215 Ω ≈ 1200 Ω

Second Way ==>

(A) Voltage of first lamp (V) = 200 V

Power of first lamp (P) = 100 W

As we all know that ====>

power = voltage x current (P = V X I) ----------- (EQ 1)

P = V X I ----------- (EQ 1)

We all know that ====>

I = V / R

In this we will put the value of I as EQ 1.

P = V X V / R

Now if we want to assume resistance ----

R = V X V / P

= 200 X 200/100

R = 400 Ω

(B) Voltage (V) of the second lamp = 220 V

Power of second lamp (P) = 40 W

As we all know that ====>

power = voltage x current (P = V X I) ----------- (EQ 1)

P = V X I ----------- (EQ 1)

We all know that ====>

I = V / R

In this we will put the value of I as EQ 1.

P = V X V / R

Now if we want to assume resistance ----

R = V X V / P

= 220 X 220/40

R = 1210 Ω (We can say that 1.2KΩ

That's it

Electric power, definition, units, formula with example

Series and Parallel combination of Resistance