Thyristor Firing Circuits Objective Questions – Part 1

In a 3-phase full converter using six SCRs, gating circuit must provide

Find the average gate power dissipation (P_gav) when the maximum allowable gate power dissipation (P_gm) = 10 kW, with a duty cycle = 50 %.

In the complete firing circuit, the driver circuit consists of

Find the amplitude of the gate current pulse, when the gate-cathode curve is given by the relation Vg = [(1+10) x Ig] The peak gate drive power is 5 Watts.

Find the triggering frequency when the average gate power dissipation = 0.3 W and the peak gate drive power is 5 Watts. The gate source has a pulse width of 20 μsec duration.

The gate-cathode curve for an SCR is given by the relation Vg = (1+10)Ig. The gate voltage source is a rectangular pulse of peak value 15 V and current = 0.659 A. Find the source resistance.

In a single pulse semi-converter using two SCRs, the triggering circuit must produce

The magnitude of gate voltage and gate current for triggering an SCR is

The duty cycle can be written as

The major function of the pulse transformer is to