Why does the multimeter not respond when measuring the capacitor?
If the digital multimeter does not respond when measuring capacitance. Firstly, confirm whether the gear and socket are correct, and secondly, the multimeter is not broken. This type of low-level error usually does not lead to errors. If the multimeter is normal and the gear is correct, it is most likely that the capacitor is broken. When the capacitor is damaged due to an open circuit (burning out) inside, the multimeter displays zero.
Another possibility is that when measuring capacitance with a multimeter, the electricity inside the capacitor must be discharged first, otherwise it may damage the internal components of the multimeter. For small capacity capacitors, simply short-circuit the two pins of the capacitor. For large capacity capacitors or cable discharges, they cannot be directly short circuited, otherwise the huge heat generated by short circuiting will cause the capacitor to bulge or even explode. The correct approach is to connect a resistor or electrical device to both ends of the capacitor, allowing the resistor or electrical device to consume the electrical energy.
When selecting electrical equipment, it is necessary to ensure that the rated voltage of the equipment is higher than the capacitor voltage
Pointer multimeter
If a pointer multimeter is used, it is possible that the capacitor gear selection is too large. The capacitance range and resistance range of a pointer multimeter are integrated, with a larger resistance range and a smaller capacitance range.
As shown in the above figure, the range of resistance x 100K is the range of capacitor C x 0.1; The gear of resistor x 1 is the gear of capacitor C x 10K.
Another situation is that the capacitor is damaged. When the capacitor is open (disconnected) internally, the multimeter pointer will not respond at all. When there is an internal short circuit (short circuit) in the capacitor, the pointer of the multimeter will stop at the zero scale of the resistor.
Under normal circumstances, when using a pointer multimeter to measure capacitance, the pointer will quickly deflect to the right, then slowly move back, and finally stop at a certain position. The larger the capacitance, the greater the right deviation angle of the pointer; The better the quality of the capacitor, the closer the pointer finally stops to infinity.
Another reason is that the capacitor has not discharged. Measure the capacitance with a pointer multimeter, and after each measurement, discharge it again (short circuit it). Some friends say that I discharged electricity the first time, right? Because every time the capacitance is measured using the capacitance mode (actually the resistance mode), the battery inside the multimeter charges the capacitance. So every time the measurement is completed and needs to be remeasured, the capacitor needs to be short circuited.
