Electronics and Communication Engineering - Power Electronics

41.
UJT can be used for
firing an SCR
turning off an SCR
both firing and turning off an SCR
none of the above
Answer: Option
Explanation:

UJT relaxation oscillator is used to provide gate pulses to SCR for triggering.


42.
In a series inverter supplying a load resistance R, the commutating elements L and C should be such that
Answer: Option
Explanation:

Load should be under damped.


43.
In a full wave converter (M - 2 connection) feeding an RLE load, the peak thyristor current is 15 A. For fully controlled bridge circuit and same load current, the peak thyristor current will be
30 A
152 A
15 A
Answer: Option
Explanation:

In both the connections the output voltage and peak thyristor current are the same. Both are full wave rectifiers.


44.
Induction heating systems require low frequency inverters.
True
False
Answer: Option
Explanation:

It uses high frequency inverter.


45.
A single phase half wave controlled rectifier circuit is feeding on RL load. The circuit has a freewheeling diode. The input voltage is v = Vm sin ωt. If I0 is the load current during the conduction of freewheeling diode, the KVL equation during the conduction of free wheeling diode is
Answer: Option
Explanation:

Load is short-circuited by free wheeling diode.