How to prevent the multimeter pointer from bending and the meter head from being burned
Regarding the use of multimeters, bending of the pointer of the multimeter will affect the measurement results. If used improperly, the meter head of the multimeter will be burned. Let's learn how to prevent these two accidents from happening.
When using a multimeter, improper operation will bend the pointer, and in more serious cases, the meter head will be burned.
To prevent such accidents from happening, pay attention to the following when using a multimeter:
1) Before measurement, estimate the size to be measured and set the range switch to the appropriate range.
If you don't know the size to be measured, you can first set the measuring range to the maximum range, and then slowly move closer to the appropriate range.
Note that when using a small range to measure a large object to be measured, the pointer is very likely to be bent.
2) When measuring resistance, the circuit under test must be cut off from the power supply.
3) When testing high voltage or large current, it is prohibited to rotate the range switch. To avoid arcing at the contacts and damaging the switch.
4) When measuring the electrolytic capacitor, short-circuit it and discharge it before measuring.
5) When the multimeter is used incorrectly, the meter head may be burned.
Preventive measures: Connect two silicon diodes in parallel to the positive and negative ends of the meter for protection (one in parallel in the forward direction and one in parallel in the reverse direction).
The conduction voltage of silicon diodes is generally greater than 0.5V. Below 0.5V, the forward resistance of silicon diodes is very large, which has little impact on the original internal resistance of the meter and can basically be ignored.
When mismeasured, the voltage increase will reduce the forward resistance of the silicon diode, and most of the current will be shunted by the diode, which plays a role in protecting the meter.
The above are the relevant methods to prevent the multimeter pointer from bending and the meter head from being burned. I hope it will be helpful to everyone.
