ADVANTAGES, DISADVANTAGES & APPLICATIONS OF SCR

Advantages:
A SCR has the following Advantages over a mechanical or electromechanical switch.

1.it has no moving parts consequently it gives noiseless operation at HF.

2. the switching speed Is very hi
3. it gives trouble free service because of small size.

4.it permits control over large current (30-100 A) in the load by means of a small gate current (a few mA).

DISADVANTAGES:

The following are the difficulties in the use of SCRs.
1.One difficulty In the use of SCR is the presence of transient pulses. These transients are accidental. And unwanted pulses of high amplitude and short duration which may appear in the anode voltage. if the pulse is in the forward direction it may cause the SCR to fire at an undesired time. If it is in the reverse direction it may cause a reverse voltage breakdown which me ruin the SCR. In circuits employing ordinary SCR. especially where high voltages and currents are involved. Special applications must be taken too guard against this transient pulses.

2.An other limitation off an ordinary transient is that it is triggered by a Positive pulse and maybe turned off by Reducing the anode voltage to about 0. Negative pulse applied to the gate will not turn off the SCR because The relatively heavy feedback current keeps the rectifier in conducting state.

APPLICATIONS:
Common areas of applications of SCR s are as follows:

1.Relay control
2.series static switch
3.phase control system
4.battery charger
5.temprerature controller
6.single source emergency lighting system
7.regulated power supplies
8.speed control of DC shunt motor
9.choppers
10.inverters
11.cyclo converters
12.protective circuits