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Instrumentation

Potentiometer Variable Resistor Working Principle

A potentiometer or a rheostat is an instrument used to measure and compare potentials without drawing any current from the circuit. Potentiometer Principle The potential difference across any length of wire of uniform cross section area is directly proportional to its length where a constant current flows through it. A potentiometer …

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AC Energy Meter Working Principle

Energy Meter Construction

Energy is the product of power and time and is measured in watt-seconds or Joule. Since the voltage and current in a DC circuit are constant values, the energy is easily computed from a measurement of power and time, $W=Pt~~~~~~~~~~Joule$ Where W is in watt seconds or Joules, P in …

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Voltmeter-Definition and Working Principle

A voltmeter is a basic device used for the measurement of electric potential or voltage, in volts. As discussed in ammeter section, any basic meter mechanism has a voltage Vm across its terminals when a full-scale current Im, flows through the meter. It follows that basic meter mechanism can be calibrated …

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Ammeter- Definition and Working Principle

An Ammeter is a device used for the measurement of current in amperes. When the current in a circuit is substantially less than an ampere, its value is determined by the use of a milliammeter or micro-ammeter, which measures full-scale currents in milli-amperes or microamperes, respectively. The symbol for the ammeter …

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