Inventory of 27 functions of capacitors in circuits

A so-called capacitor is an electronic component that holds and releases an electrical charge. The main working principle of a capacitor is charging and discharging, and of course, rectification, oscillation and other functions. In addition, structure of capacitor is very simple, it mainly consists of two positive and negative electrodes and an insulating medium sandwiched between them, so type of capacitance is mainly determined by electrodes and insulating medium.

1. Filter Capacitor

A filter capacitor is connected between positive and negative poles of DC voltage to filter out unnecessary AC components in DC power supply and make DC power supply smooth. Generally, a large capacity electrolytic capacitor is used, and other types can also be connected in parallel in circuit. Small capacitor for filtering high frequency AC current.

2. Decoupling Capacitor

A decoupling capacitor is connected in parallel between positive and negative poles of power supply of amplifier circuit to prevent parasitic oscillations caused by positive feedback generated by internal resistance of power supply.

3. Shunt Capacitor

In an AC and DC signal circuit, connect a capacitor to both ends of resistor in parallel, or connect a specific point of circuit to a common potential to establish a path for AC signal or pulse signal to avoid AC signal component due to passing through resistor Drop attenuation pressure.

4. Communication capacity

In AC signal processing circuit, it is used to connect signal source and signal processing circuit, or as an interstage connection between two amplifiers, used to turn off DC current, pass AC signal or pulse signal, and make DC operating point front and rear amplifier circuits did not affect each other.

5. Tuning Capacitor

Connected to both ends of oscillation coil of resonant circuit, it plays role of selecting oscillation frequency.

6. Pad capacity

This is an auxiliary capacitor connected in series with main capacitor of resonant circuit. Adjusting it can reduce frequency range of oscillation signal and greatly increase oscillation frequency at low end.

7. Compensation tank

The compensation capacitor is an auxiliary capacitor connected in parallel with main capacitor of resonant circuit, by adjusting which it is possible to expand frequency range of the oscillation signal.

8. Neutralization Capacitor

Connected in parallel between base and emitter of a triode amplifier to form a negative feedback circuit to suppress self-oscillations caused by interelectrode capacitance of triode.

9. Frequency stabilization capacitor

In an oscillatory circuit, it plays a role in stabilizing the oscillation frequency.

10. Time Capacitor

In an RC time constant circuit, it is connected in series with resistor R to determine charging and discharging times.

11. Accelerating Capacitor

Connected to generator feedback circuit to speed up positive feedback process and increase amplitude of oscillation signal.

12. Reduce capacity

In circuit of UHF high-frequency head, a capacitor is connected in series to reduce length of oscillatory inductor.

13. Clapo condenser

In a capacitive three-point oscillating circuit, a capacitance connected in series with an inductive oscillatory coil can eliminate effect of transistor junction capacitance on frequency stability.

14, tin capacitor

In a capacitive three-point oscillation circuit, a capacitor connected in parallel with both ends of inductive oscillation coil can eliminate influence of transistor junction capacitance and facilitate vibration of oscillator at high-frequency end.

15. Stabilizing cap

In a frequency discriminator, it is used to stabilize amplitude of output signal.

16. Pre-emphasis capacitor

In order to avoid attenuation and loss of frequency division value during processing of audio modulation signal, high frequency component of RC is set to increase network capacity.

17. Compensating Capacitor

In order to restore original audio signal, it is necessary to attenuate high frequency components and noise in pre-distorted audio signal and set RC capacitance in network.

18. Phase-shifting capacitor

Phase shifting capacitors are capacitors used to change phase of an AC signal.

19. Feedback Capacitor

Connected between input and output of amplifier, output signal is returned to input capacitor.

20. Step-Down Current-Limiting Capacitor

It is connected in series with an AC circuit, using capacitance characteristics of a capacitor with respect to AC current to limit AC current, thus forming a voltage divider circuit.

21. Flyback Capacitor

Used in horizontal scan output circuit and connected between collector and emitter of horizontal output tube to generate a high-voltage horizontal scan sawtooth wave reverse pulse, and its withstand voltage is typically greater than 1500 volts.

22, correction capacitor S

In series with deflection clamp circuit, it is used to correct extended linear distortion at edge of the kinescope.

23. Bootstrap Boost Capacitor

Using charging and discharging energy storage characteristics of a capacitor to increase potential of a specific point in a circuit so that potential of that point is twice voltage value of power supply terminal.

24. Capacitor to eliminate bright spots

It is installed in video amplifier circuit, which is used to eliminate residual bright spot capacitor on kinescope when it is turned off.

25. Soft start capacitor

It is usually connected to switch tube base of switching power supply to prevent excessive surge current or high peak voltage from being added to switch tube base when power is turned on, which could damage switch. a tube.

26. Start Capacitor

Connected in series with auxiliary winding of a single-phase motor to provide motor with starting phase-shifting AC voltage, and disconnected from auxiliary winding after motor is running normally.

27. Run Capacitor

Connected in series with auxiliary winding of a single-phase motor to provide phase-shifted AC current to auxiliary winding of motor. When motor is running normally, it is connected in series with secondary winding.