Why thyristor is used in rectifier?

When used in rectifier circuits, thyristors allow current to be controlled more accurately than diodes, which can only be ON or OFF. A thyristor can be triggered to allow current to pass in a graduated manner, by firing (switching on the thyristor) at a precise time, therefore controlling the conduction angle.

What are the conditions for a thyristor to conduct?

The conditions needed to make the thyristor conduct, then, are: forward bias – the anode more positive than the cathode; a sufficiently large pulse of current flowing into the gate; a sufficiently large current then flowing from anode to cathode.

What is the purpose of a thyristor?

Thyristors are mainly used where high currents and voltages are involved, and are often used to control alternating currents, where the change of polarity of the current causes the device to switch off automatically, referred to as “zero cross” operation.

How can a conducting thyristor be turned off?

Device description Thus, a thyristor behaves like a normal semiconductor diode after it is turned on or “fired”. The GTO can be turned on by a gate signal, and can also be turned off by a gate signal of negative polarity. Turn off is accomplished by a “negative voltage” pulse between the gate and cathode terminals.

What are the conditions for a thyristor to conduct and how can a conducting thyristor be turned off?

Controlled Rectifiers The thyristor would begin to conduct with a current that can be described at every instance by: If the current falls below the holding current IH then the thyristor switches off. Every positive halve period of the supply voltage this pattern repeats itself.

How is thyristor turned off?

Thus, a thyristor behaves like a normal semiconductor diode after it is turned on or “fired”. The GTO can be turned on by a gate signal, and can also be turned off by a gate signal of negative polarity. Turn off is accomplished by a “negative voltage” pulse between the gate and cathode terminals.