How to judge whether the cell phone flash capacitor is damaged?

Check the electrolytic capacitor with the resistance of multimeter. Electrolytic capacitors have positive and negative leads. When checking whether it is good or not, the resistance of electrolytic capacitor with low withstand voltage (6V or 10V) should be placed in R× 100 or R×1K. Electrolytic capacitors such as red stylus (negative electrode connected to capacitor) and black stylus (positive electrode connected to internal power supply of multimeter) are good. The larger the electrolytic capacitor capacity, the longer the charging time and the slower the pointer swings. Judging the positive and negative leads of electrolytic capacitor with multimeter. If the sign of the positive and negative leads is unclear, it can be judged according to the characteristics of small leakage current (large resistance value) when they are directly connected and large leakage current when they are reversely connected. The specific method is: touch the two leads of the capacitor with a red and black probe, and record the magnitude of the leakage current (resistance value) (resistance value indicated when the pointer swings back), then short-circuit the positive and negative leads of the capacitor, and then measure the leakage current after the red and black probes are switched. Judging from the indication that the leakage current is small, the lead wire in contact with the black stylus is the positive terminal of the electrolytic capacitor. It is difficult to distinguish the polarity of electrolytic capacitors with small leakage current by this method. Check the variable capacitor with a multimeter. The variable capacitor has a set of stators and a set of rotors. Use multimeter resistance to check whether there is contact between the rotor and stator. Connect the rotor and stator with red and black probes respectively, rotate the shaft handle, and the ammeter pointer does not move, indicating that there is no short circuit (contact) between the rotor and stator. If the pointer swings, the capacitor is short-circuited. Roughly identify the quality of capacitors above 5000PF with multimeter resistance file. Capacitance above 5000PF can be roughly identified by multimeter resistance file (below 5000PF, it can only be judged whether the capacitance is broken down internally). When checking, put the resistance range at the high end of the range, and the two probes are in contact with both ends of the capacitor respectively. At this point, the pointer swings quickly and then recovers and is reversed. The swing amplitude is larger than the first time, and then it recovers. Such a capacitor is good. The larger the capacitor capacity, the greater the swing of the instrument pointer and the longer the recovery time of the pointer. We can compare the capacity of two capacitors according to the swing of the instrument pointer.