How do capacitors work?
Time：2021.08.06
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Let me talk about circuits and capacitors first.
<The circuit is the road, and the charge is the car>
If a circuit is compared to a road, the movement of electric charge is like the flow of traffic.
<Impedance is a rough road>
In the case of uneven roads, the speed of the car will slow down but it will still move towards the destination. In the circuit, impedance generates heat and consumes energy (Joule electricity).
<The power supply (battery) is a device that carries a potential difference>
The power supply is a device with E[V] potential difference connected at both ends. This is the same reason that a car uses an elevator to automatically move to a position with a height of t[m].
So what is a capacitor?
Then let's talk about the situation when the power supply is equipped with a capacitor.
<Capacitor is a parking lot>
Capacitors can store charge. If you compare a circuit to a road, the capacitor is like a parking lot. The positive and negative ends of the circuit must have the same amount of charge stored.
<Capacitor has the ability to store charge>
The standard for how much charge a capacitor can store is called the capacitance value, which is shown in equation (1).
It can be seen from the formula (1) that ① the electrode area S is enlarged ② the distance between the electrodes is shortened ③ the use of a material with a high dielectric constant can increase the capacitance value.
The unit of capacitance is F (Farad) in the SI unit system. When a voltage of 1V (potential difference) is applied to a certain conductor and a charge of 1C (coulomb) is stored, the capacitance value is 1F.
＜Operation of capacitor＞
The charge stored in the capacitor flows to the load current when the switch S1 is OFF and S2 is ON.
According to the state of the capacitor, a stable electric lamp emits light when the power supply voltage is unstable. In addition, when a 1uF capacitor is applied with a voltage of 10V, the energy stored by the capacitor is 50W. In order to still have the energy supplied by the capacitor when the power is turned off, an electronic product with a rated power of 50W can be made that can be operated in 1 second.
＜Capacitors block direct current, only AC current can be passed on＞
Capacitors cannot be energized with direct current. If they are repeatedly charged and discharged, charging current and discharging current will flow repeatedly in the capacitor.
This phenomenon can be observed through the appearance of the capacitor whether the current flows through the capacitor.
Because of these characteristics, many capacitors are used in the circuit.
It is necessary to choose the most suitable product to suit its purpose.
