What is a Thyristor?

What is a Thyristor?

Thyristor definition

SCR for short, is a high-power electrical component, also known as thyristor. It has the advantages of small size, high efficiency and long life. In the automatic control system, it can be used as a high-power driving device to realize the control of high-power equipment with low-power control. It has been widely used in AC and DC motor speed control system, power regulation system and servo system.

Thyristor structure

It is composed of 4 layers of semiconductor material, with three PN junctions and three external electrodes.

Thyristor conduction conditions

• One is to apply A positive voltage between its anode A and cathode K

• The second is to input a forward triggering voltage between the control pole G and the cathode K

Main parameters of Thyristor

• Average current in rated on-state IT

• Forward blocking peak voltage VPF

• Reverse blocking peak voltage VPR

• Trigger voltage VGT

• Maintain current IH

Thyristor classification

• Ordinary thyristor

• Bidirectional thyristor

• Reverse conduction thyristor

• Gate turn-off thyristor (GTO)

• BTG thyristor

• Temperature controlled thyristor

• Optically controlled thyristor

Purpose of Thyristor

Controlled rectification