Use a multimeter to check for faulty circuits/faulty components
A multimeter, also known as a multimeter, multimeter, multimeter, or multimeter, is an indispensable measuring instrument in power electronics and other departments. Its main purpose is to measure voltage, current, and resistance. Multimeters are divided into pointer multimeters and digital multimeters according to their display modes. It is a multifunctional and multi range measuring instrument. Generally, a multimeter can measure DC current, DC voltage, AC current, AC voltage, resistance, and audio level. Some can also measure AC current, capacitance, inductance, and some parameters of semiconductors (such as β).
Capacitor detection
Step 1: Set the multimeter to capacitor mode and select the appropriate range
Step 2: Place the probes of the multimeter on both ends of the pins of the two components
After testing with a multimeter, we can clearly see that the small capacitor is measured by the reading. Read the reading on the multimeter and compare it with the actual value marked on the capacitor. If these two values are close, it means the capacitor is normal. Our capacitor is marked with 10uf, and the measured value of 13.8uf can be said to be close.
Looking at the second picture again, it is obvious that the multimeter reading is zero, which is enough to indicate that the capacitor of this drum has indeed burned out. If you want to repair it, you can find a capacitor with the same parameters to replace this one.
Detection of diodes
After discussing the capacitance, let's talk about the detection of diodes. The method of diode detection is relatively simple compared to capacitance detection, because our multimeter comes with a diode gear and only one position, so there is no need to consider the range. We adjust it to the diode gear, and then connect the positive pole of the multimeter to the anode of the diode, and the negative pole of the multimeter to the positive pole of the diode. If you see a reading on the multimeter display screen, it means that the diode in the circuit is normal (some multimeters may sound) and has not been broken down.
Inductance detection
Inductance is a very important component in mobile phone chargers, and almost every charger cannot do without it. Therefore, it is necessary for us to learn a method to detect inductance. "Inductance", which we learned in high school, is equivalent to a short circuit to DC current. We can make good use of this and combine it with the diode block on the multimeter.
We all know that if the red and black probe of the diode block is directly connected to a multimeter, it will make a sound. If it is not connected to a multimeter, it will not make a sound. Similarly, if it is connected to an inductor, it will also make a sound. Give it a try. Everyone should pay attention that before connecting, except for the buzzer, there is only one symbol of the diode in the upper right corner of the multimeter display screen.
