thyristor turn on

JDT

Joined Feb 12, 2009
657
Some reasons I can think of:-
1. Because you can - once the thyristor is on it stays on until commutated.
2. Allows the use of small pulse transformers for isolating the gate signal. Useful when the thyristor is at power-line voltages.
3. Reduces average power dissipation in the driver circuit (short high-current pulse).
4. Guarantees that the thyristor will turn off when commutated (forward current falls to low value) without having to worry about removing the gate current first.

Sometimes, when controlling difficult loads - mainly inductive, or brushed motors where there may be momentary breaks in the current flow - the thyristor is fed with a series of pulses throughout the on period instead of just 1 pulse at the start.
 
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