Several requirements for replacing capacitors
Whether the parameters meet the requirements
There are many parameters in the capacitor, such as withstand voltage value, capacity number, working temperature, frequency characteristic capacity deviation and so on. When the capacitor is replaced, the main attention is paid to the two parameters of the withstand voltage value of the capacitor and the capacity of the capacitor. The capacitance value of the capacitor before and after the replacement is as consistent as possible, which is related to the stability of the circuit after it is repaired.
In addition, the withstand voltage value should be the same before and after the replacement. If you can't find a consistent voltage capacitor, you can find one with a larger withstand voltage value.
Are the capacitor types the same
The main functions of capacitors, such as filtering, coupling, delay components, etc., but if the types of capacitors are different in some special circuits, it will affect the performance of the circuit. For example, some capacitors have poor high-frequency characteristics, such as electrolytic capacitors. It is one of them, the high frequency characteristics of ceramic capacitors are better.
Therefore, in high frequency circuits, ceramic capacitors are generally used instead of electrolytic capacitors.
The working voltage of the specific circuit
When replacing the capacitor, you need to know the specific value of the capacitor's operating voltage in the circuit, otherwise it will cause breakdown due to the voltage in the circuit exceeding the capacitor's withstand voltage value, and even cause "explosion" consequences. The key is to look at the specific working voltage of the capacitor in the circuit. Regardless of the withstand voltage of the original capacitor, if the withstand voltage value of the replaced capacitor is not lower than the voltage value of the circuit, it is enough.
Some capacitors are polarized, such as electrolytic capacitors. In addition to the withstand voltage value greater than or equal to the original value when replacing, it should also be noted that the positive and negative poles cannot be reversed.
In addition, many circuit boards use SMD capacitors. When replacing SMD capacitors, they can be replaced as long as the color and size are the same. But pay attention to the frequency stabilized SMD capacitors of the single-chip microcomputer. It is best to choose the same, so as not to affect the operation of the single-chip microcomputer stability.