Classification and characteristics of various capacitors (I)

Capacitors are commonly used electronic components in electronic devices. The structure and characteristics of several commonly used capacitors are briefly introduced below for your reference.

1. Aluminum electrolytic capacitors:

It is made of an aluminum cylinder as a negative electrode, a liquid electrolyte inside, and a bent aluminum strip as a positive electrode. It also needs to be treated by DC voltage to form an oxide film on the positive electrode sheet as a medium. It is characterized by large capacity, large leakage, poor stability, positive and negative polarity, suitable for power supply filtering or low frequency circuits. When used, the positive and negative poles should not be reversed.

2. Tantalum electrolytic capacitor:

It uses a metal crucible or crucible as a positive electrode, a dilute sulfuric acid or the like as a negative electrode, and an oxide film formed on the surface of a crucible or a crucible as a medium. Its characteristics are: small size, large capacity, stable performance and long life. The insulation resistance is large. Good temperature performance and used in equipment with high requirements.

3. ceramic capacitor:

Use ceramic as the medium. A silver layer is sprayed on both sides of the ceramic substrate, and then fired into a silver film as a plate. Its characteristics are: small size, good heat resistance, low loss, high insulation resistance, but small capacity, suitable for high frequency circuits. Ferroelectric ceramic capacitors have large capacity, but the loss and temperature coefficient are large, which is suitable for low frequency circuits.

4. Mica capacitors:

The electrode plate is sprayed with a metal foil or a silver layer on the mica plate, and the plate and the mica are laminated one by one, and then die-cast in the bakelite powder or sealed in an epoxy resin. Its characteristics are: low dielectric loss and large insulation resistance. Small temperature coefficient for high frequency circuits.