Six common questions and answers about chip capacitors, do you know the answers?

There are many questions about SMD capacitors. The editor has collected six common questions on the Internet to answer them for everyone!

1. I learned on the Internet that capacitors are used in electric fans. What role does the capacitor play in electric fans?

Answer: The role of activation. The start of an electric fan depends on a capacitor, and it cannot be started without a capacitor. But when the fan is working normally, the capacitor has no effect.

2. Since capacitors are needed to start the fan, doesn't it mean that all motors also need capacitors? Otherwise, it can't be started, is that the case?

Answer: No. Not all motors need capacitors, such as three-phase asynchronous motors without capacitors, DC motors without capacitors, exhaust fan motors, etc., do not need capacitors to start.

3. Many people want to know the specifications of capacitors, so what are the contents of the specifications of capacitors?

Answer: The main parameters of capacitor specifications are: voltage, capacitance, capacitance error, loss factor, equivalent series resistance, temperature coefficient, operating temperature range, leakage current, life, etc.

4. Tantalum capacitors are divided into positive and negative poles. Is there a very simple way to distinguish the positive and negative poles of tantalum capacitors?

Answer: ① SMD: One end of the SMD tantalum capacitor is marked with a horizontal line, which is the positive electrode of the SMD tantalum capacitor, and the other end is the negative electrode;

② Plug-in: The long leg of the lead tantalum capacitor is the positive pole, and the short leg is the negative pole.

5. How to judge whether the capacitor of the fan or motor is broken?

Answer: ①Turn the fan blades of the fan or the rotor of the motor with a screwdriver after powering on the motor. If it can turn, it proves that the capacitor is broken;

②Remove the capacitor, connect both ends of the capacitor with alternating current for a few seconds, and then take it out (note that you must not touch it with your hands after taking it out), and then short-circuit both ends of the capacitor wire, and observe whether the sound is loud during discharge, if the sound is not loud It means that the capacity of the capacitor is not enough, otherwise it is normal. However, it should be noted that these two methods are only applicable to AC capacitors, and DC capacitors cannot be tested by the above methods.

6. If we want to buy capacitors on the market, what models and sizes are there to choose from?

Answer: The capacitance depends on the purpose. If it is a small capacitor for patch, it may have 0.01PF. 1PF and 1.5PF are common capacitors. If it is a plug-in capacitor, its capacity is relatively large, as small as 1UF, 2.2UF, as large as 4700UF, and more. The unit of electrolytic capacitor used for plug-in is generally UF, so the capacity is larger. In addition, it is very important for the capacitor to have a withstand voltage value. When choosing a capacitor, you must purchase a suitable capacitor according to the needs of the circuit. If the withstand voltage value is too low, the circuit will be damaged. If the capacitance value is too low, the circuit will not work properly.