Wien’s Bridge

The Wien’s bridge use in AC circuits for determining the value of unknown frequency. The bridge measures the frequencies from 100Hz to 100kHz. The accuracy of the bridges lies between 0.1 to 0.5 percent. The bridge is used for various other applications like capacitance measurement, harmonic distortion analyser and in the HF frequency oscillator. The…

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Digital Instrument

Definition: The instrument which represents the measurand value in the form of the digital number is known as the digital instruments. It works on the principle of quantization. The quantization is the process of converting the continuous input signal into a countable output signal. The construction of the digital instrument is very complex, and their…

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Vacuum Tube Voltmeter (VTVM)

Definition: The voltmeter which uses the vacuum tube for amplifying the measurand AC and DC voltage is known as the vacuum tube voltmeter (VTM). The vacuum tube increases the sensitivity of the voltmeter because of which it can detect the signal of very weak strength. The electronic voltmeter is used for measuring the voltage of…

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Electronic Voltmeter

Definition: The voltmeter which uses the amplifier for increases their sensitivity is known as the electronic voltmeter. It is used for measuring the voltages of both the AC and DC devices. The electronic voltmeter gives the accurate reading because of high input resistance. The moving coil voltmeter is not able to detect the low voltages.…

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Magnetoresistor

Definition: The resistance of some of the metal and the semiconductor material varies in the presence of the magnetic field, this effect is called the magnetoresistance. The element which has these effects is known as the magnetoresistor. In other words, the magnetoresistor is a type of resistor whose resistance varies with the magnetic field. The magnetoresistor…

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Resistive Transducer

Definition: The transducer whose resistance varies because of the environmental effects such type of transducer is known as the resistive transducer. The change in resistance is measured by the ac or dc measuring devices. The resistive transducer is used for measuring the physical quantities like temperature, displacement, vibration etc. The measurement of the physical quantity is…

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Bolometer

Definition: The bolometer is a device used for detecting and measuring the heat and radiation of  Microwave energy or RF.  It uses the temperature sensitive resistive element who resistance changes with the temperature. The Thermistor and Barretter are the examples of the commonly used resistive element. The circuit of the bolometer is in the form…

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Recording Instrument

Definition: The recording instrument is defined as the instrument which records the continuous variation of the magnitude of an electrical quantity for a particular period. It is used in a placed where the continuous reading of circuit conditions is required. The record is used for future reference or computational work. The recording instruments take readings…

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Resolver

Definition: The resolver is a rotary transformer used for conversion of the angular position of the shaft into Cartesian coordinates. It is an analogue device which has a digital counterpart. The output of the transducer has two signals, one is proportional to the sine of the angle and other is proportional to the cosine of…

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Integrating Instrument

Definition: The integrating instrument measures the total energy supplied by the circuit in a given interval of time. It is independent of the rate at which the total energy consumed. The watt hour meter is the example of integrating instruments. This type of meter directly measures the energy in watt hour. Types of Integrating Instruments…

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