Circuits Diagram

Welcome to Circuits Diagram!

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 12:12:00 +0000

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Notice: This blog is under construction, you can view the circuit diagrams of topics below:

Battery Related:

24V Lead acid Battery Charging circuit

555 Timer IC:

555 Timer Oscillator

Ramp generator circuit-using 555 timer IC

Police siren using NE555

Voltage doubler circuit using NE555

UPS and Inverter:

How an Inverters Work

Simple 40W inverter

100W inverter circuit

Simple UPS

60W inveter using transistors

12 V DC to 120 V AC Inverter

make custom gifts at Zazzle

Our recent Posts!

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 12:02:00 +0000

Battery Related:
24V Lead acid Battery Charging circuit

555 Timer IC:
555 Timer Oscillator
Ramp generator circuit-using 555 timer IC
Police siren using NE555
Voltage doubler circuit using NE555

24V Lead acid Battery Charging circuit

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 11:50:00 +0000

Description.
This lead acid battery charger circuit is designed in response to a request from Mr.Devdas .C. His requirement was a circuit to charge two 12V/7AH lead acid batteries in series.Anyway he did not mentioned the no of cells per each 12V battery. The no of cells/battery is also an important parameter and here I designed the circuit assuming each 12V battery containing 6 cells. When two batteries are connected in series, the voltage will add up and the current capacity remains same. So two 12V/7AH batteries connected in series can be considered as a 24V/7AH battery.

The circuit given here is a current limited lead acid battery charger built around the famous variable voltage regulator IC LM 317. The charging current depends on the value of resistor R2 and here it is set to be 700mA. Resistor R3 and POT R4 determines the charging voltage. Transformer T1 steps down the mains voltage and bridge D1 does the job of rectification. C1 is the filter capacitor. Diode D1 prevents the reverse flow of current from the battery when charger is switched OFF or when mains power is not available.

Circuit diagram:

Notes.

Assemble the circuit on a good quality PCB.

T1 can be a 230V primary, 35V/3A secondary step down transformer.

If 3A Bridge is not available, make one using four 1N5003 diodes.

LM317 must be fitted with a heat sink.

R2 = 0.85 ohm is not a standard value. You can obtain it by combining a 6.2 ohm and 1 ohm resistors in parallel.

F1 can be a 2A fuse.

To setup the charging voltage, power ON the charger and hook up a voltmeter across the output terminals and adjust R4 to make the voltmeter read 28V. Now the charger is ready and you can connect the batteries.

This charger is specifically designed for two 12V/7AH/6 cell lead acid batteries in series OR a 24V/7AH/12 cell lead acid battery.

555 Timer Oscillator

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 11:42:00 +0000

A voltage-controlled oscillator (VCO) using the timer 555 is shown in figure.

The circuit is sometimes called a voltage-to-frequency converter because the output frequency can be changed by changing the input voltage.

As discussed in previous blog posts, pin 5 terminal is voltage control terminal and its function is to control the threshold and trigger levels. Normally, the control voltage is ++2/3V_CC because of the internal voltage divider. However, an external voltage can be applied to this terminal directly or through a pot, as illustrated in figure, and by adjusting the pot, control voltage can be varied. Voltage across the timing capacitor is depicted in figure, which varies between +V_controland ½ V_control. If control voltage is increased, the capacitor takes a longer to charge and discharge; the frequency, therefore, decreases. Thus the fre quency can be changed by changing the control volt age. Incidentally, the control voltage may be made available through a pot, or it may be output of a transistor circuit, op-amp, or some other device.

Ramp generator circuit-using 555 timer IC>>

Ramp generator circuit-using 555 timer IC

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 11:25:00 +0000

We know that if a capacitor is charged from a voltage source through a resistor, an exponential waveform is produced while charging of a capaci tor from a constant current source produces a ramp. This is the idea behind the circuit. The circuit of a ramp generator using timer 555 is shown in figure. Here the resistor of previ ous circuits is replaced by a PNP transistor that produces a constant charging current.

Charging current produced by PNP constant current source is

i_C= Vcc-V_E/ R_E

where V_E= R₂/ (R1 + R2) * V_CC+ V_BE

When a trigger starts the monostable multivibrator timer 555 as shown in figure, the PNP current source forces a constant charging into the capacitor C. The voltage across the capacitor is, therefore, a ramp as illustrated in the figure. The slope of the ramp is given as

Slope, s = I/C

Police siren using NE555>>

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Police siren using NE555

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 11:18:00 +0000

Description.

A lot of electronic circuits using NE555 timer IC are already published here and this is just another one.Here is the circuit diagram of a police siren based on NE55 timer IC. The circuit uses two NE555 timers ICs and each of them are wired as astable multivibrators.The circuit can be powered from anything between 6 to 15V DC and is fairly loud.By connecting an additional power amplifier at the output you can further increase the loudness.

IC1 is wired as a slow astable multivibrator operating at around 20Hz @ 50% duty cycle and IC2 is wired as fast astable multivibrator operating at around 600Hz.The output of first astable mutivibrator is connected to the control voltage input (pin5) of IC2. This makes the output of IC2 modulated by the output frequency of IC1, giving a siren effect. In simple words, the output frequency of IC2 is controlled by the output of IC1.

Circuit diagram:

Notes.

The circuit can be assembled on a Perf board.
I used 12V DC for powering the circuit.
Instead of using two NE55 timer ICs, you can also use a single NE556 timer.
NE556 is nothing but two NE555 ICs in one package.
Refer the datasheets of NE555 and NE556 to have a clear idea.
Speaker can be a 64ohm, 500mW one.

Voltage doubler circuit using NE555>>

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Voltage doubler circuit using NE555

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 11:06:00 +0000

Description.
The circuit diagram of a very simple voltage doubler using NE555 timer is shown here. Here IC NE555 is wired as an astable mutivibrator operating at around 9KHz. The base of the two transistors (Q1 and Q2) is shorted and output of the astable multivibrator (pin 3) is connected to it. When the output of astable multivibrator is low, Q1 will be OFF and Q2 will be ON. The negative terminal of the capacitor C3 will be shorted to ground through T2 and it will be charged to the input supply voltage. When the output of the astable multi vibrator is high, transistor Q1 will be ON and transistor Q2 will be OFF. The capacitor C4 will be charged to the voltage across capacitor C3 plus the input supply voltage (that is double the input voltage). This is how the circuit works.

This voltage doubler circuit can deliver only up to 50mA output current and above that current limit the output voltage will be dramatically reduced. The actual output voltage will be around 19V for a 12V DC input and also the output voltage will be a bit unstable. Anyway, for low current applications this circuit is well enough.

Circuit diagram:

Notes:

The circuit can be assembled on a vero board.

The output current should not be allowed to exceed 70mA.

IC1 must be mounted on a holder

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How an Inverters Work

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 09:38:00 +0000

Everyone uses some kind of electronic gadget while in their motor-home, SUV or car. You might listen to your MP3 player, check fordirections on your global positioning system (GPS) or play a portable video game. These types of electronic devices can be recharged or powered by plugging them into the cigarette lighter (or power port) in your vehicle.

But what if you want to use something a little more elaborate while you're on the open road? Maybe you want to make toast, watch an LCD TV, or perhaps even write an article on your laptop computer. These devices plug into regular wall outlets, not cigarette lighters. Making sure your electronic gear gets the juice it needs while on the road isn't a simple matter of finding the right adapter. You need a power inverter.

Power inverters convert direct current (DC), the power that comes from a car battery, into alternating current (AC), the kind of power supplied to your home and the power larger electronics need to function. What kind of power inverter is the right one for the job? How do you install one? And how exactly does an inverter change the current from one form to another? In this article, we'll explore all the positives and negatives of DC to AC power inverters.

Why Do I Need To Convert from DC to AC?

From DC to AC and Back Again

Ironically, if you use an AC inverter to power a computer or television, the power supply in the device is converting the 120-volt alternating current into a much lower voltage direct current. The sensitive electronic circuits in these devices need low, regulated voltages to work, so you're actually converting DC to AC so it can be changed back into DC again. You can't use straight direct current without the AC to DC inverter because the device's power supply needs the AC power in order to properly step down and regulate the voltage.

Most cars and motor homes derive their power from a 12-volt battery. In some cases, a heavy-duty 24-volt battery might be used. It's important to know your vehicle's voltage because the voltage rating of the inverter you select should match the voltage of the battery. In either case, the battery provides direct current. This means that the current flows continuously from the negative terminal of the battery, through the completed circuit and back to the positive terminal of the battery. The flow is in one direction only, hence the name direct current. The ability to provide direct current power is inherent to the nature of batteries.

Direct current is very useful, but batteries can generally only provide relatively low-voltage DC power. Many devices need more power to function properly than DC can provide. They're designed to run on the 120-volt AC power supplied to homes in the U.S. Alternating current or AC, constantly changes polarity, sending current one way through the circuit, then reversing and sending it the other way. It does this very quickly -- 60 times per second in most U.S. electrical systems. AC power works well at high voltages, and can be "stepped up" in voltage by a transformer more easily than direct current can.

An inverter increases the DC voltage, and then changes it to alternating current before sending it out to power a device. These devices were initially designed to do the opposite -- to convert alternating current into direct current. Since these converters could basically be run in reverse to accomplish the opposite effect, they were called inverters.

Up next, how do inverters invert?

Making Direct current to Alternate

The earliest AC power inverters were electro-mechanical devices. Direct current would flow down one end of a circuit with an electromagnet. As soon as the current hit the magnet, the magnet would activate. This would pull a wire attached to a spring arm, forcing the wire to contact the circuit. This would change the flow of the current to the other side of the circuit, cutting power from the electromagnet. As soon as the magnet released, the spring would snap the wire back, allowing the current to flow on the other side of the circuit, once again activating the magnet. These old inverters were known for making a buzzing sound.

Modern inverters use oscillator circuits to accomplish the same process. They're made with transistors or semiconductors, so there's no longer the need for a spring arm flipping back and forth to alternate the current.

It's not quite as simple as that, however. Alternating current forms a sine wave. The output of an inverter is a very square wave, not like the smooth, round wave of a perfect sine. Some devices are inherently sensitive to the signal produced by an AC wave. Typically, these are devices that receive or broadcast some kind of signal, such as audio or video equipment, navigation devices or sensitive scientific equipment. You can see or hear the square waveform on a television as lines on the screen or a steady buzz or hum.
Cleaning up the sine wave requires a series of filters, inductors and capacitors. Inexpensive inverters have little or no filtering. The alternating current they produce has a very square wave, which is fine if you just want to make coffee or run something with a simple electric motor. If you need a smoother sine wave, you'll need an inverter with better filtering. Of course, better filtering also costs a little more. Inverters can get extremely expensive, even costing thousands of dollars, that is, if you're looking for an inverter with a smooth sine. The good news: Given a large enough budget, you can purchase an AC power inverter that produces virtually perfect AC sines. In fact, some high-end DC to AC inverters can make sine waves that are even smoother than the AC power supplied to your house.
In the next section, we'll learn how to pick the right inverter for the job.

Watts, Peaks and Surges

Hand Wash Only
You won't be powering a washing machine or clothes dryer with an inverter, so you'd better get out the washboard and the clothesline. Most U.S. washers and dryers run on 220 volts, and inverters aren't designed to produce the kind of power these machines need.

The first step in selecting an inverter is to match the inverter to the voltage of the battery you'll be using for power. In the majority of cases, you'll be using a 12-volt battery, so you would want to select a 12-volt inverter.
The next step is to determine which devices you plan to power with the inverter. Look for a label somewhere on each device that tells you the wattage it requires to operate. The wattage rating of your inverter must exceed the total wattage of all the devices you plan to run simultaneously. For instance, if you wanted to run a 600-watt blender and a 600-watt coffee maker at the same time, you'd need an inverter capable of a 1,200-watt output. However, if you knew you would never be making coffee and fruit smoothies at the exact same time, you'd only need a 600-watt inverter.
Unfortunately, things aren't quite that simple. Devices that have electric motors, as well as some televisions, draw a higher wattage than their normal operating wattage rating when they first start up. This is known as peak or surge, and this information should also be listed on the device's label. Most inverters also have a peak rating, so make sure the inverter's peak rating is higher than the peak wattage of the device you intend to power. Microwaves are a special case. As an example, you may know that your microwave is a 500-watt microwave. This is actually the cooking wattage. The power wattage might be twice that amount. Again, check the label on the device to make sure.
If you plan to run your inverter through the cigarette lighter in your car, it's a safe bet that you won't be using any high-wattage devices. In fact, if you try to pass more than about 400 watts through a cigarette lighter connection, it will fail -- and it might even start a fire in your vehicle.
The final specification to look for is the wave output of the inverter. If you'll be powering any of the equipment that is sensitive to square waves, look for an inverter with a "perfect sine" wave output. Be prepared for sticker shock -- a perfect sine inverter can cost almost 10 times as much as the same wattage inverter with a modified sine output. Modified sine means that the current is run through some filtering, so it isn't a square wave, but it isn't totally smooth either.
On the next page, we'll explain how to install an inverter.
Inverter Installation
Inverters are very easy to install. Most of them are "plug and play" devices, especially smaller, low-wattage inverters. These inverters have a cable with a plug that fits into the cigarette lighter on your car or truck. They're meant to be portable, so there's no other mounting to be done.

DC AC Power Inverters
If you have serious power requirements, you might need an inverter like this. It requires a heavy-duty 24-volt battery and has an output of 3,500 watts. You could run almost anything with this, including air-conditioners and other large appliances.
If you purchase an inverter that allows higher wattages, proper installation becomes a bit more critical. Below 400 watts, the cigarette lighter connection is still a possibility, but wattages above that require direct connection to the battery. The inverter's input cables have clips that can be attached to the terminals of the battery, similar to a set of jumper cables. If the installation is to be permanent, the cables can be bolted to the terminals. The inverter itself can be mounted anywhere, although it should be in a place with good air flow. Inverters generate a fair amount of heat, and they use cooling fans and heat dissipation fins to prevent overheating. Larger, heavier inverters have mounting holes in their chassis so they can be bolted to any surface. Obviously, with a permanent installation, you'll probably want to bolt your converter in place, but this isn't absolutely necessary. It's possible to simply place the inverter in a secure, stable position, clip the leads to the battery and plug in.
Just what does an inverter look like, anyway? Well, the smallest inverters can fit in your pocket, while higher-wattage models are roughly the size and weight of a large dictionary. As a general rule: The higher the wattage, the larger and heavier the inverter. At the top of the inverter wattage scale, some inverters can be more than two feet long and weigh over 30 pounds.
Modern inverters have some built in safety features that make them even easier to use. Some models sound an alarm when the battery's voltage gets too low. This is more of a convenience, but depending on what sort of equipment you're powering, it could also be a valuable safety feature. Inverters typically have automatic shut-off capabilities, too. If the unit detects a current overload or an overheating situation, it will shut down to lessen or prevent the chance of a fire. Inverters can also shut off in the event of a short circuit, such as a piece of metal falling into the chassis or the inverter getting wet. Short circuit shut-off is an effective way to prevent electrocution.
So how much is all of this going to cost, you ask? You can buy a modified sine inverter rated for continuous power of 200 watts for about $25 and the price of a 6,000-watt modified sine inverter can approach $1,000. Pure sine inverters cost much more -- these can be more than $200 for an inverter rated at just 300 watts.
Simple 40W inverter>>

Simple 40W inverter

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 09:25:00 +0000

Description
This is the schematic of a simple 40W , 12 to 220 V inverter.You don’t believe, this is simple and cheap and working for me for last 4 years.The heart of the circuit is a CD 4047 IC which is wired as an astable multi vibrator here.Resistance and Capacitance at pin 1&2 determines the out put frequency.Here it is set to 60Hz.Due to this a two 180 degree out of phase ,120 Hz , 50% dutycycle waveforms will appear at pin 10 & 11.These waves are amplified by the complementary symmetry amplifier made of transistors BC 337 & TIP 3055 to drive the out put transformer.Don’t get feared of the technical terms, just wire it on a all purpose PCB.It is simple and will work.Don’t worry about the transformer windings ,buy a 220-110-0 primary,12-0-12 secondary , <50W transformer.You can select output voltage of 110V or 220V by a two way switch using such a tranformer.Don’t worry if you don’t have such a transformer, a simple 220 to 12-0-12 will also do the trick sacrificing the 110V option or vice versa.The best way to get a transformer is to break all useless electronic devices in your trash.Most probably you will find the transformer or more components needed here!

Circuit Diagram:

Tips :
First wire to oscillator part only.Then check out put Pin 10 &11 of CD4047 to obtain the required wave forms ( two 120Hz ,180 degree out of phase,50% duty cycle waves.
Then connect transistors ,transformer and load (25 W bulb for test).See it working!.

100W inverter circuit>>
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100W inverter circuit

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 08:54:00 +0000

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Description

Here is a 100 Watt inverter circuit using minimum number of components.I think it is quite difficult to make a decent one like this with further less components.Here we use CD 4047 IC from Texas Instruments for generating the 100 Hz pulses and four 2N3055 transistors for driving the load.

The IC1 Cd4047 wired as an astable multivibrator produces two 180 degree out of phase 100 Hz pulse trains.These pulse trains are preamplifed by the two TIP122 transistors.The out puts of the TIP 122 transistors are amplified by four 2N 3055 transistors (two transistors for each half cycle) to drive the inverter transformer.The 220V AC will be available at the secondary of the transformer.Nothing complex just the elementary inverter principle and the circuit works great for small loads like a few bulbs or fans.If you need just a low cost inverter in the region of 100 W,then this is the best.

Circuit diagram:

Notes.

A 12 V car battery can be used as the 12V source.

Use the POT R1 to set the output frequency to50Hz.

For the transformer get a 9-0-9 V , 10A step down transformer.But here the 9-0-9 V winding will be the primary and 220V winding will be the secondary.

If you could not get a 10A rated transformer , don’t worry a 5A one will be just enough. But the allowed out put power will be reduced to 60W.

Use a 10 A fuse in series with the battery as shown in circuit.

Mount the IC on an IC holder.

Remember,this circuit is nothing when compared to advanced PWM inverters.This is a low cost circuit meant for low scale applications.

Simple UPS>>

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Simple UPS

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 08:45:00 +0000

Description.

This is the circuit diagram of a simple UPS that can deliver 12V unregulated and 5V regulated DC. The transformer T1 steps down the mains voltage to 12V AC and then the bridge B1 rectifies it. The rectified signal is smoothed by the capacitor C1.When the mains supply is available the battery will be charged via diode D3 and the regulator IC gets supply via diode D5. 12V and 5V DC will be available at the output terminals. When mains supply is not available the battery supplies current to the regulator IC and to the 12V DC terminal through diode D4.Also, the diode D3 blocks reverse flow of current during battery mode. Capacitors C2 and C3 acts as filters.

Circuit Diagram:

Notes.

Assemble the circuit on a good quality PCB.

The transformer T1 can be a 230V AC primary, 12V secondary,3A step-down transformer.

The bridge B1 can be a 2A bridge. If such a bridge is not available, make one using four 1N4007 diodes.

The capacitor C1 must be rated at least 25V.

60W inveter using transistors>>

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60W inveter using transistors

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 08:41:00 +0000

Description.
Here is the circuit diagram of a fully transistorized inverter that can drive up to 60W loads. Transistors Q1 and Q2 forms a 50Hz astable multivibrator. The output from the collector of Q2 is connected to the input of the Darlington pair formed by Q3 and Q4.Similarly the output of Q1 is coupled to the input of the pair Q5 and Q6. The output from the Darlington pairs drive the final output transistors Q7 and Q8 which are wired in the push pull configuration to drive the output transformer.

Circuit Diagram:

Notes:

The circuit can be assembled on a vero board.

T1 can be a 230V primary to 9-0-9V, 6A secondary transformer.

Transistors Q4, Q6, Q7 and Q8 must be fitted with heat sinks.

Use a 12V, 7Ah battery for powering the inverter.

Slight adjustments can be made on the value of R3 and R4 to get exact 50Hz output.

12 V DC to 120 V AC Inverter >>

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12 V DC to 120 V AC Inverter

noreply@blogger.com (Universal Store) — Thu, 08 Apr 2010 08:17:00 +0000

This is the bacis of inverter circuit diagram. The circuit will convert 12V DC to 120V AC. This circuit can handle up to 1000Watts supply depends the T1, T2 and transformer used. Please see the note.

Component list:

Part	Total Qty.	Description
C1, C2	2	68 uf, 25 V Tantalum Capacitor
R1, R2	2	10 Ohm, 5 Watt Resistor
R3, R4	2	180 Ohm, 1 Watt Resistor
D1, D2	2	HEP 154 Silicon Diode
Q1, Q2	2	2N3055 NPN Transistor (see “Notes”)
T1	1	24V, Center Tapped Transformer (see “Notes”)
MISC	1	Wire, Case, Receptical (For Output)

Notes:

1. Q1 and Q2, as well as T1, determine how much wattage the inverter can supply. With Q1,Q2=2N3055 and T1= 15 A, the inverter can supply about 300 watts. Larger transformers and more powerful transistors can be substituted for T1, Q1 and Q2 for more power.
2. The easiest and least expensive way to get a large T1 is to re-wind an old microwave transformer. These transformers are rated at about 1KW and are perfect. Go to a local TV repair shop and dig through the dumpster until you get the largest microwave you can find. The bigger the microwave the bigger transformer. Remove the transformer, being careful not to touch the large high voltage capacitor that might still be charged. If you want, you can test the transformer, but they are usually still good. Now, remove the old 2000 V secondary, being careful not to damage the primary. Leave the primary in tact. Now, wind on 12 turns of wire, twist a loop (center tap), and wind on 12 more turns. The guage of the wire will depend on how much current you plan to have the transformer supply. Enamel covered magnet wire works great for this. Now secure the windings with tape. Thats all there is to it. Remember to use high current transistors for Q1 and Q2. The 2N3055’s in the parts list can only handle 15 amps each.
3. Remember, when operating at high wattages, this circuit draws huge amounts of current. Don’t let your battery go dead .
4. Since this project produces 120 VAC, you must include a fuse and build the project in a case.
5. You must use tantalum capacitors for C1 and C2. Regular electrolytics will overheat and explode. And yes, 68uF is the correct value. There are no substitutions.
6. This circuit can be tricky to get going. Differences in transformers, transistors, parts substitutions or anything else not on this page may cause it to not function.

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