10 tips for using a multimeter
The basic principle of a multimeter is to use a sensitive magneto electric DC ammeter (microampere meter) as the meter head. When a small current passes through the meter, there will be a current indication. But the meter head cannot pass high currents, so it is necessary to shunt or reduce the voltage by connecting some resistors in parallel or series on the meter head, in order to measure the current, voltage, and resistance in the circuit. Now let the electrician's home editor introduce the usage method of the multimeter for everyone.
1, A voltage below 36V is considered safe voltage. When measuring voltages above 36V DC and 25V AC, it is necessary to check whether the probes are reliably connected, correctly connected, and well insulated to avoid electric shock.
2, When changing functions and ranges, the probe should be away from the testing point, and the correct function and range should be selected during testing to prevent accidental operation.
3, To measure DC voltage, first turn the range switch to the corresponding DCV range, and then connect the test probe across the tested circuit. The voltage and polarity at the point where the red probe is connected are displayed on the screen.
4, For AC voltage measurement, first turn the range switch to the corresponding ACV range, and then connect the test probe across the tested circuit.
5, For direct current measurement, first turn the range switch to the corresponding DCA position, and then connect the instrument in series to the circuit being measured.
6, For AC current measurement, first turn the range switch to the corresponding ACA position, and then connect the instrument in series to the tested circuit.
7, Resistance measurement: Turn the range switch to the corresponding resistance range and connect the two probes across the measured resistance.
8, For capacitance measurement, turn the range switch to the corresponding capacitance range, connect the test probe across the measured capacitance and both ends for measurement, and pay attention to polarity if necessary.
9, Pole tube and on-off test, set the range switch to gear. Connect the red probe to the positive terminal of the diode and the black probe to the negative terminal of the diode. When testing the continuity of a circuit, connect the probe to both ends of the circuit to be tested. If the buzzer sounds, the circuit will be turned on, otherwise the circuit will be turned off.
10, Measure the amplification factor of the transistor, set the range switch to the hFE position, and determine whether the transistor being measured is NPN or PNP. Insert the emitter, base, and collector into the corresponding holes.
