Photoelectric Cell | Types & Applications

Photoelectric cell is the device which converts light energy into electrical energy. Depending upon the different photoelectric effects employed, the photoelectric cells are of following 3 types. Photoemissive cell Photoconductive cell Photovoltaic cell Photoemissive cell This cell is based on the fact that electrons are emitted from a photo-sensitive surface by the action of light. … Read morePhotoelectric Cell | Types & Applications

Beat Frequency Oscillator | Working & Limitations

Beat Frequency Oscillator is a type of oscillator used to obtain variable frequency output in the audio frequency range. The basic working of this type of oscillator is as follows. Working Principle Figure 1 shows a block diagram of beat frequency oscillator (BFO). It uses two Radio frequency (RF) oscillators. One is fixed frequency oscillator … Read moreBeat Frequency Oscillator | Working & Limitations

Blondel’s theorem | Power in Poly-Phase System

Statement Blondel’s theorem states that if a network is supplied through P conductors, the total power is measured by adding the readings of P wattmeters so arranged that a current element of a wattmeter is in each line and the corresponding voltage element is connected between that line and a common point. Note: If the … Read moreBlondel’s theorem | Power in Poly-Phase System

Wheatstone Bridge | Working Principle & Applications

A Wheatstone bridge is used for the accurate measurement of resistance. The Wheatstone bridge works on the principle of null deflection, i.e. the ratio of their resistances are equal, and no current flows through the galvanometer. The general arrangement of Wheatstone bridge circuit is shown in the fig. 1. It is a four arms bridge circuit … Read moreWheatstone Bridge | Working Principle & Applications

Difference Between Current & Potential Transformer

The differences between Current Transformer (CT) and Potential Transformer (PT) are given below: S.No. Current Transformer (CT) Potential Transformer (PT) 1. It is connected in series with the power circuit. It is connected in parallel with the power circuit. 2. Its secondary is connected to an Ammeter. Its secondary is connected to a Voltmeter. 3. Its secondary … Read moreDifference Between Current & Potential Transformer

Measurement of Medium Resistance

Resistance is classified into three categories as low, medium and high resistance. Medium Resistance ranges from 1Ω to 0.1 MΩ. The different methods used for the measurement of Medium resistance are as follows: Ammeter Voltmeter method Substitution Method Wheatstone Bridge Method Ohmmeter Method Substitution Method In this section, we will learn about Measurement of Medium Resistance by Substitution Method. … Read moreMeasurement of Medium Resistance

Measurement of Low, Medium & High Resistance

Resistance is classified into three categories for the sake of Measurement. Different categories of Resistance are measured by the different techniques. They are classified as Low Resistance: Resistance having value 1Ω or below are kept under this category. Medium Resistance: This category includes Resistance from 1Ω to 0.1 MΩ. High Resistance: Resistance of the order of … Read moreMeasurement of Low, Medium & High Resistance

Permanent Magnet Moving Coil or PMMC Instruments

PMMC stands for Permanent Magnet Moving Coil. PMMC Instruments are the most accurate type for the measurement of DC current or voltage. Construction of PMMC Instruments Permanent Magnet Moving Coil or PMMC Instruments consists of following components: Moving Coil Magnet System Control Spring Damping Pointer and Scale 1. Moving Coil The moving coil made up … Read morePermanent Magnet Moving Coil or PMMC Instruments

Single Phase Electrodynamometer Power Factor Meter

Construction The construction of a single phase Electrodynamometer Power Factor Meter is shown in fig. 1. It consists of a fixed coil which acts as the current coil. This coil is split up into two parts and carries the current of the circuit under test. Therefore, the magnetic field produced by this coil is proportional to the main current. Two identical pressure coils A … Read moreSingle Phase Electrodynamometer Power Factor Meter

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