The working principle and main function of thyristor

1. The working principle of thyristor is:

1. To make the thyristor turn on, one is to apply a forward voltage between its anode A and cathode K, and the other is to input a positive trigger voltage between its control electrode G and cathode K. After the thyristor is turned on, release the button switch, remove the trigger voltage, and still maintain the on state.

2. However, if a reverse voltage is applied to the anode or control electrode, the thyristor cannot be turned on. The function of the control pole is to turn on the thyristor by applying a positive trigger pulse, but it cannot be turned off. Turning off the conducting thyristor can cut off the anode power supply (switch S in Figure 3) or make the anode current less than the minimum value for maintaining conduction (called the sustaining current). If an AC voltage or a pulsating DC voltage is applied between the anode and the cathode of the thyristor, the thyristor will turn off by itself when the voltage crosses zero.

2. The functions of thyristor in the circuit are as follows:

1. Converter/rectifier.

2. Adjust the pressure.

3. Frequency conversion.

4. Switch.

One of the most important functions of the SCR is to stabilize the current. Thyristors are widely used in automatic control, electromechanical fields, industrial electrical and household appliances. The thyristor is an active switching element. It is usually kept in a non-passing state until it is triggered by a less control signal or “ignited” to make it pass. Once it is ignited, it will remain even if the trigger signal is withdrawn. In the channel state, to make it cut off, a reverse voltage can be applied between the anode and the cathode or the current flowing through the thyristor diode can be reduced to below a certain value.