Daily Dose Of Electrical Electronics Engineering

What is a Hermetic Seal?

2010-03-28T01:54:00.000+05:30

What is a Hermetic Seal A hermetic seal is a seal, which is practically airtight. Such seals are secure against water vapor and other foreign bodies and thus ensures proper working of its contents. Hermetic seals are vastly found in semiconductor electronics and optical devices.

What is Transformer Oil?

2010-03-28T01:20:00.000+05:30

Transformer Oil Transformer oil, or insulating oil, is usually a highly-refined mineral oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil-filled transformers, some types of high voltage capacitors, fluorescent lamp ballasts, and some types of high voltage switches and circuit breakers. Its functions are to insulate, suppress corona and

What is a Magnetometer?

2010-03-22T15:54:00.000+05:30

What is a Magnetometer A magnetometer is a scientific instrument used to measure the strength and/or direction of the magnetic field in the vicinity of the instrument. Applications Magnetometers are used in ground-based electromagnetic geophysical surveys (such as magnetotellurics) to assist with detecting mineralization and corresponding geological structures. Airborne geophysical surveys use

What is a Drive or Motor Controller?

2010-03-22T14:16:00.000+05:30

What is a Drive or Motor Controller A motor controller or drive is a device that serves to govern in some predetermined manner, the performance of an electric motor. A motor controller or drive might include a automatic or manual means for starting and stopping the motor, selecting forward or reverse direction of rotation, selecting and regulating the speed, regulating or limiting the torque,

What is a Drum Motor?

2010-03-22T13:56:00.000+05:30

What is a Drum Motor A Drum Motor, also called a motorized pulley, is a highly efficient geared motor drive enclosed within a steel shell providing a single component driving pulley for conveyor belts and the like. The Drum Motor consists of a synchronous or asynchronous electric motor fixed to a stationary shaft at one end of the drum and directly coupled through the motor’s rotor pinion to a

What are Rotary Electrical Connectors? Advantages of Rotary Electrical Connectors

2010-03-22T01:41:00.000+05:30

Advantages of Rotary Electrical Connectors over Slip Ring and Brushes The conventional brush slip ring mechanism to convert a mechanically rotating electrical system to a static one, as in the case of generators, comes across various disadvantages like wear and tear, larger size, noise, etc. Rotary Electrical Connectors make use of ball bearings and hence rotary electrical connectors have

What is a Norator?

2010-03-20T13:31:00.001+05:30

A norator is a theoretical linear, time invariant, one port network which arbitrary current and voltage across its terminals. It represents a controlled voltage or current source with infinite gain. When inserted in the schematics of a circuit, a norator provides whatever current and voltage the outside circuit demands.

What is a Nullator?

2010-03-20T13:28:00.002+05:30

A nullator is a theoretical linear, time invariant, one port network which has zero current and voltage across its terminals. A nullator has the properties of both a short circuit and an open circuit simultaneously. They are neither current or voltage sources, yet both at the same time.

What is a Nullor?

2010-03-20T13:02:00.001+05:30

A nullor is a theoretical two port network composed of a nullator at its input and a norator at its output. Nullors represent an ideal amplifier with infinte current, voltage, transconductance and transimpedence gain. All the four transmission parameters of this two port network is zero.

Properties of an Ideal Operational Amplifier(Op Amp)

2010-03-20T12:57:00.000+05:30

Properties of an Ideal Op Amp (Operational Amplifier) 1. Infinite Open Loop Gain 2. Infinite Bandwidth - the opamp can respond to all frequencies 3. Infinite Input Impedance 4. Zero Input Current - no current drawn by input terminals as input impedence is infinite 5. Zero Output Impedance 6. Infinite Slew Rate - change from one output state to another takes zero time 7. Infinte Common Mode

What is Surface Tensiometer?

2010-03-19T03:00:00.000+05:30

A surface tensiometer is a device designed to measure the surface tension of liquids. A goniometer is used to measure the surface tension and interfacial tension of a liquid using the pendant or sessile drop methods. A drop is produced and the profile is then captured using a goniometer/tensiometer. The software then analyses the profile of the drop and makes a series of critical measurements.

What is a Goniometer? Define Goniometer

2010-03-19T02:59:00.000+05:30

A goniometer is an instrument that either measures angle or allows an object to be rotated to a precise angular position. Goniometers are classified on the basis of their filed of application, In the field of Surface Science, a Contact Angle Goniometer is used to measure the static contact angle, advancing and receding contact angles, and surface tension. A gonioreflectionometer is used to

What is Divergence Theorem?

2010-03-16T13:54:00.000+05:30

Divergence Theorem Divergence Theorem states that the volume integral of the Divergence of a vector field A, is equal to the total outward flux of the vector through the closed surface bounding the volume.

What is Divergence? Define Divergence

2010-03-16T13:52:00.002+05:30

What is divergence? Define divergence. Divergenceof a vector field A at a point, is defined as the net outward flux of A per unit volume as volume tends to zero. Divergence operator takes Vector as input and gives Scalar as output

What are flux lines?

2010-03-16T13:50:00.000+05:30

Graphical representation of field variations Field variations can be represented graphically by using directed field lines, called flux lines or stream lines. These flux lines indicate at each point the direction and magnitude of the vector filed. Direction is indicated by the arrowhead, and the magnitude is indicated by the concentration of flux lines at a point or the length of the lines.

What is Gradient? Define Gradient

2010-03-16T13:48:00.000+05:30

What is Gradient? Define Gradient. Gradient of a scalar is defined as the vector which represents both in magnitude and direction, the maximum space rate of change of the scalar. Consider a scalar A. Consider two constant A surfaces (surfaces throughout which A is constant) S1 and S2. Let A be A1 in on S1 and A1 + dA on S2. Consider a point P1 on S. Consider point P2 on S2 such that P1P2 is

Phase Velocity and Group Velocity

2010-03-16T13:43:00.005+05:30

Group Velocity Group Velocity of the a wave is the velocity with which the changes in amplitude of the wave propagates. It is given by Vg =dw/dk where w = angular frequency k = wave number

Phase Velocity and Group Velocity

2010-03-16T13:43:00.004+05:30

Phase Velocity Phase velocity of a wave is the velocity with which a particular phase of the wave (say, the crest) propagates. It is given by Vp = lambda/T Vp = w/k where lambda = wavelength T= time period of the wave w = angular frequency k= wave number

What is Crawling

2010-03-07T18:10:00.005+05:30

Crawling Sometimes, a 3 phase induction motor shows a tendency to run at a stable speed, which is much lower than the synchronous speed, 1/7th of Ns and is unable to pick up to its normal speed. This phenomenon is known as crawling. The main cause of crawling is the presence of harmonics in the flux set up by the stator windings. Due to the non linearity in the magnetization characteristics,

What is a Slip Ring Rotor

2010-03-07T02:22:00.001+05:30

Points in Slip Ring Induction Rotor Rotor terminals are connected to slip rings at the end of the shaft Rotor Windings are wound for the same number of windings as the stator windings Rotor terminals are usually connected in star Working : A lever mechanis is used which has two positions, START and RUN. When in START position, the brushes are kept in contact with the slip rings ans resitances

What is a Squirrel Cage Rotor

2010-03-07T02:17:00.001+05:30

Points on Squirrel Cage Rotor The rotor bar assembly is in the shape of a squirrel cage, hence the name 90% of all induction motors are squirrel cage, because i is extremely rugged Rotor core has rotor stampings punched into it Copper bars are driven through the slots and ends are welded to form end rings The rotor bars are slightly alligned to the shaft axis due to skew provided while stacking

What are the Disadvantages of Three Phase Induction Motors

2010-03-07T01:44:00.002+05:30

Disadvantages 1. Speed decreases as load increases, unlike Synchronous motors. The spped control auxiliarry can cost upto ten times the cost of the motor 2. Low starting torque, unlike Direct Current motors.

What are the Advantages of Three Phase Induction Motors

2010-03-07T01:43:00.001+05:30

Advantages of Three Phase Induction Motors 1. Simple in construction : So large numbers can be constructed inexpensively 2. Extremely rugged construction 3. Low cost : As construction is simple 4. Reliable : As it is extremely rugged 5. Low Maintenance : Only periodic dusting is required 6. Simple starting arrangement : Small motors can be started directly 7. High Efficiency : Full load

What is Electrical Resonance

2010-03-06T17:20:00.001+05:30

Electrical resonance occurs in an electrical circuit when the impedance between the input and output is minimum. Consider a circuit with a capacitor and inductance in series. When the capacitor is charged, it stores some energy in its electric field. When this charge gets discharged through the inductor, a current flows through, a varying current through the coil causes a build up of magnetic

What is Resonance

2010-03-06T17:18:00.001+05:30

When a system is excited by energy, it tends to osccilate. The system oscillates at much higher amplitudes at certain frequencies than at other frequencies. This tendency of a system is called Resonance, and the frequencies corresponding to high amplitudes are called resonant frequencies. Example. Acoustic resonance of musical instruments, resonance of electrical circuits, nuclear magnetic