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  2. Short-circuit test - Wikipedia

    en.wikipedia.org/wiki/Short-circuit_test

    An ammeter is connected in series with the primary winding. A voltmeter is optional since the applied voltage is the same as the voltmeter reading. Now with the help of a variac, the applied voltage is slowly increased until the ammeter gives a reading equal to the rated current of the HV side. After reaching the rated current of the HV side ...

  3. Ammeter - Wikipedia

    en.wikipedia.org/wiki/Ammeter

    Demonstration model of a moving iron ammeter. As the current through the coil increases, the plunger is drawn further into the coil and the pointer deflects to the right. An ammeter (abbreviation of ampere meter) is an instrument used to measure the current in a circuit. Electric currents are measured in amperes (A), hence the name. For direct ...

  4. Class of accuracy in electrical measurements - Wikipedia

    en.wikipedia.org/wiki/Class_of_accuracy_in...

    Ideally the measuring device should not affect the circuit parameters i.e., the internal impedance of the ammeter should be zero (no voltage drop over the ammeter) and the internal impedance of the voltmeter should be infinite (no current through the voltmeter). However, in actual case, ammeters have a low but non zero impedance and voltmeters ...

  5. Current sensing - Wikipedia

    en.wikipedia.org/wiki/Current_sensing

    The generated signal could be analog voltage or current or a digital output. The generated signal can be then used to display the measured current in an ammeter, or can be stored for further analysis in a data acquisition system, or can be used for the purpose of control. The sensed current and the output signal can be: Alternating current input,

  6. Electrical measurements - Wikipedia

    en.wikipedia.org/wiki/Electrical_measurements

    Ammeter and Voltmeter on a power supply. Electrical measurements are the methods, devices and calculations used to measure electrical quantities. Measurement of electrical quantities may be done to measure electrical parameters of a system.

  7. Multimeter - Wikipedia

    en.wikipedia.org/wiki/Multimeter

    If the most significant digit cannot take all values from 0 to 9 it is generally, and confusingly, termed a fractional digit. For example, a multimeter which can read up to 19999 (plus an embedded decimal point) is said to read 4 + 1 ⁄ 2 digits. By convention, if the most significant digit can be either 0 or 1, it is termed a half-digit; if ...

  8. Galvanometer - Wikipedia

    en.wikipedia.org/wiki/Galvanometer

    Such meters are often calibrated to read some other quantity that can be converted to a current of that magnitude. The use of current dividers, often called shunts, allows a meter to be calibrated to measure larger currents. A meter can be calibrated as a DC voltmeter if the resistance of the coil is known by calculating the voltage required to ...

  9. Ayrton shunt - Wikipedia

    en.wikipedia.org/wiki/Ayrton_shunt

    The voltage drop across parallel branches is always equal. When all resistances are placed in parallel with R m maximum sensitivity of ammeter is reached. [5] Ayrton shunt is rarely used for currents above 10 amperes. [6] m1 = I1/Im , m2 = I2/Im, m3 = I3/Im