Check before multimeter measurement
A multimeter is a multifunctional and multi range measuring instrument that is indispensable in electronic and electrical technology. A general multimeter can measure DC current, DC voltage, AC current, AC voltage, resistance, and audio level. Some can also measure capacitance, inductance, and some parameters of semiconductors (such as β). If distinguished simply by display mode, multimeters can be divided into pointer multimeters and digital multimeters.
The three basic functions of a multimeter are to measure resistance, voltage, and current, so the predecessors called it a multimeter. Nowadays, multimeters have added many new functions, especially digital multimeters, such as measuring capacitance value, transistor amplification factor, diode voltage drop, etc. There is also a talking digital multimeter that can broadcast measurement results in language.
Operation steps
Check whether the battery voltage and power generation are normal, and whether the battery pile head is severely rusted. Many car owners think that the leakage result is a battery problem or a generator problem;
Inquire with the car owner if there have been any recent repairs, installations, or collision related disassembly and assembly;
Remove the negative terminal of the battery, set the multimeter to current mode * high, connect the red probe to the negative wire, and connect the black probe to the battery post and fix it;
Turn off all electrical appliances inside and outside the car, lock the doors, observe the current level, adjust to the appropriate gear, and record;
Wait for about 20 minutes; After all modules of the vehicle enter sleep mode, read the accurate static discharge current;
The static current is generally 0.03A (i.e. 30mA), refer to the maintenance manual for details, not exceeding 50mA;
If the static current is too high, we can check by unplugging the fuses and relays one by one, observing the magnitude of the static current;
Pre measurement inspection
Observe whether the multimeter needle is set to 0. If it is not in position 0, turn the zero adjustment screw to set it to position 0.
Check the integrity of the two probes and leads. This is particularly crucial when measuring high AC voltages to prevent electric shock accidents.
Check the lead plug and tighten it if it is loose. Sometimes looseness is caused by the loosening of the fastening nut of the socket, and at this time, the watch case needs to be tightened before repair.
