The difference between capacitor and battery

They are all electrical components, and they are all energy storage components. The common capacitance is that the two metal electrodes are separated by an insulating material, and then the structure of the outer casing is protected. The electrolytic capacitor also has an electrolyte. Generally, the capacitor is used for coupling, filtering, decoupling, etc. They are all used as "instant power supply", so the energy provided is not very large, so there is not much energy required to store the capacitor. The battery is also two electrodes, but usually has a large amount of electrochemical material, which converts electrical energy into chemical energy during charging, and converts chemical energy into electrical energy during discharge. The characteristics of the battery and capacitor are a bit close.
The main differences are:

1. The battery stores a lot of power and the capacitors are stored less.
2. The battery is slower and the capacitor is charging very fast.
3. Most capacitors can be charged at high currents, but batteries are less likely to be charged at high currents.

With the development of electronic technology, the capacity of capacitors is now getting bigger and bigger, and the battery is gradually replaced in many places. For example, many faucets that are automatically flushed now use supercapacitors (capacitors with very large capacity) instead of batteries, and real-time. Many of the clock circuits (most of which consume power in the micro-ampere level) also use supercapacitors instead of batteries. Last year, China also developed supercapacitors for automotive power supply, replacing the batteries to power the car engines.
Capacitors are used in many ways, mainly as follows:
1. DC blocking: The role is to prevent DC from passing and let the AC pass.
2. Bypass (decoupling): Provides a low impedance path for certain parallel components in an AC circuit.
3. Coupling: as a connection between two circuits, allowing AC signals to pass through and be transmitted to the next stage of the circuit
4. Filtering: This is very important for DIY. The capacitance on the graphics card is basically this effect.
5. Temperature compensation: compensates for the influence of other components on the temperature, and compensates to improve the stability of the circuit.
6. Timing: Capacitors are used in conjunction with resistors to determine the time constant of the circuit.
7. Tuning: System tuning of frequency-dependent circuits such as cell phones, radios, and televisions.
8. Rectification: Turns the semi-closed conductor switching element on or off at a predetermined time.
9. Energy storage: Stores electrical energy for release when necessary. For example, camera flash, heating equipment, etc. (The energy storage level of some capacitors is now close to the level of lithium batteries, and the energy stored in one capacitor can be used by one mobile phone for one day.