How to use the universal meter

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2023-02-16 09:05

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Measuring voltage: select a good range when measuring voltage (or current). If you use a small range to measure large voltage, there will be a danger of burning the meter; If a large range is used to measure small voltage, the pointer deflection is too small to read. The selection of measuring range shall make the pointer deflect to about 2/3 of the full scale. If the magnitude of the measured voltage is not known in advance, the highest range gear shall be selected first and then gradually reduced to the appropriate range.
A. Measurement of AC voltage: place one change-over switch of the multimeter at the AC and DC voltage range, and the other change-over switch at the appropriate range of AC voltage. The two probes of the multimeter can be connected in parallel with the circuit or load under test.
B Measurement of DC voltage: place one change-over switch of the multimeter at the AC and DC voltage ranges, and the other change-over switch at the appropriate range of DC voltage, and connect the "+" probe (red probe) to the high potential, and the "-" probe (black probe) to the low potential, that is, let the current flow in from the "+" probe and out from the "-" probe. If the probe is connected reversely, the pointer of the meter head will deflect in the opposite direction, which is easy to bend the pointer.
(6) Current measurement: when measuring the DC current, place one change-over switch of the multimeter at the DC current gear, and the other change-over switch at the appropriate range of 50uA to 500mA. The current range selection and reading method are the same as the voltage. When measuring, the circuit must be disconnected first, and then the multimeter is connected in series to the circuit under test in the direction of current from "+" to "-", that is, the current flows in from the red probe and out from the black probe. If the multimeter is connected in parallel with the load by mistake, the internal resistance of the meter head is very small, which will cause short circuit and burn the instrument. The reading method is as follows: actual value=indicated value × Range/full deviation
(7) Measuring resistance: When measuring resistance with a multimeter, the following methods shall be followed:
A Select the appropriate magnification gear. The scale line of the ohm gear of the multimeter is uneven, so the selection of the magnification gear should make the pointer stay at the thinner part of the scale line, and the closer the pointer is to the middle of the scale, the more accurate the reading is. Generally, the pointer should be between 1/3~2/3 of the scale.
B Ohm zero. Before measuring the resistance, the two probes should be short-circuited, and the "ohm (electrical) zero adjustment knob" should be adjusted at the same time, so that the pointer just points to the zero position on the right of the ohm scale line. If the pointer cannot be adjusted to the zero position, the battery voltage is insufficient or there is a problem inside the instrument. And every time the magnification gear is changed, the ohm shall be adjusted to zero again to ensure accurate measurement.
C Reading: the reading of the meter head multiplied by the multiplier is the resistance value of the measured resistance.

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