Electrothermal Instrument

Definition: The instrument whose working depends on the heating effects of the measuring current is known as the electrothermal or electrothermic instrument. This device is used for measuring the high-frequency current. The most significant advantage of this type of instrument is that it measures the high range frequency current more than the Moving Iron and…

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Difference Between Random & Systematic Error

The most significant difference between the random and the systematic error is that the random error occurs because of the unpredictable disturbances caused by the unknown source or because of the limitation of the instrument. Whereas, the systematic error occurs because of the imperfection of the apparatus. The other differences between the random and the systematic error…

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Classification of Measuring Instruments

The instrument used for measuring the physical and electrical quantities is known as the measuring instrument. The term measurement means the comparison between the two quantities of the same unit. The magnitude of one of the quantity is unknown, and it is compared with the predefined value. The result of the comparison obtained regarding numerical…

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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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Electrodynamometer Wattmeter

Definition: The instrument whose working depends on the reaction between the magnetic field of moving and fixed coils is known as the Electrodynamo-meter Wattmeter. It uses for measuring the power of both the AC and DC circuits. The working principle of the Electrodynamometer Wattmeter is very simple and easy. Their working depends on the theory…

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Ballistic Galvanometer

Definition: The galvanometer which is used for estimating the quantity of charge flow through it is called the ballistic galvanometer. The working principle of the ballistic galvanometer is very simple. It depends on the deflection of the coil which is directly proportional to the charge passes through it. The galvanometer measures the majority of the charge…

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Voltmeter

Definition: The instrument which measures the voltage or potential difference in volts is known as the voltmeter. It works on the principle that the torque is generated by the current which induces because of measurand voltage and this torque deflects the pointer of the instrument. The deflection of the pointer is directly proportional to the…

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Ammeter Shunt

Definition: The ammeter shunt is the device which provides the low resistance path to the flow of current. It connects in parallel with the ammeter. In some of the ammeter, the shunt is inbuilt inside the instrument while in others it is externally connected to the circuit. Why Shunt Connect in parallel with Ammeter? The ammeter designs…

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Ammeter

Definition: The meter uses for measuring the current is known as the ammeter. The current is the flow of electrons whose unit is ampere. Hence the instrument which measures the flows of current in ampere is known as ampere meter or ammeter. The ideal ammeter has zero internal resistance. But practically the ammeter has small…

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Volt-Ratio Box

Definition: The volt-ratio box measures the high voltage. The construction of the volt-ratio box is very simple. It consists the simple resistive potential divider which has many tapping on the input side. The whole arrangement of the volt-ratio box is placed inside the wooden box. The volt-ratio box gives the accurate result of measure voltage.…

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