What is involved in multimeter calibration?

Multimeter calibration includes measurement and adjustment of various multimeter or multi -scope measuring modes. The most common measurement methods are the AC voltage/direct current (AC/DC), resistance measurement AC/DC and DC. There are different multimeter calibration devices and settings that serve as a calibration link, depending on the required accuracy. Unlike digital multimeters, analog multimeters must be calibrated to maintain accuracy. Analog multimeters usually have adjustable resistors called cutting resistors that can be used to compensate for different conditions. Different factors such as resistors, sensitivity to the movement of the meter and battery voltage may affect the accuracy of multimeters. Some analog mulčátny also uses internal battery for voltage and current measurement. In a multimeter that uses the movement of the meter with 50 microompers in full scale, the manufacturer indicates a DC full scale with a direct current of 10, 50, 250 and 500 volts (VDC). There are four in this caseVoter position position that measures DC tension.

The necessary overall resistance of the meter of 1 kiloOhm (K-OHM) can be calculated. In a full 10 VDC scale, the current into the voltmeter must be in a full scale of 50 microompers and the overall resistance is 10 volts (V)/50 micro leaders or 200 k-ohm. The total resistance is 200 k-ohm, so the necessary resistance to the range is 200 k-ohm less 1 k-ohm or 199 k-ohm. Calibration is a matter of using solid resistance and adjustable resistance to approximately 199 k-ohm. A typical example can be 180 k-ohm firm resistance in series with 20 k-ohm resistor for 10 VDC.

For multimeter AC calibration, the circuit is the same as for a DC multimeter circuit with an added rectifier. The diodes in the perimeter of the rectifier convert AC to the relative DC half or full-weave pulses that are filtered and limited to control the movement of the meter. With the correct selection of resistance of the series, the values ​​are similar to valuem of the actual multimeter of root average square (RMS).

In the DC ammet, which measure DC currents, the movements of meters are parallel to very low resistors. Calibration is usually done by adjusting the resistance in the series with the movement of the meter. When the movement of the meter is 50 microampers parallel to the 0.1 ohm resistor, it corresponds to the full scale of 50 micro -Germans to a small voltage of 0.05 VDC via the ammeter. This corresponds to a current of 0.5 ampere (A) and a full -scale label is 500.05 millameres (MA).