Name : Mohsin Rauma Roll no. : 9 Sem. : 4th

it is an SCR whose state is controlled by the light falling upon a silicon semiconductor layer of the device.

Anode

Gate

Cathode

Anode

Cathode

Gate

Some of the areas of application for the LASCR include optical light controls, relays, phase control, motor control and a variety of computer application

The maximum currents (rms) and power (gate) ratings for LASCRs commercially available today are about 3A and 0.1W.

One interesting application of an LASCR is in the AND and OR circuits

Load

LASCR1

LASCR2

Supply

Load

Supply

LASCR1 LASCR2

The LASCR is most sensitive to light when the gate terminal is open. It’s sensitivity can be reduced and controlled somewhat by the insertion of the gate resistor.

It is the semiconductor analog of the electromechanical relay.

It offers complete isolation between input and switching element.

The energizing current can be passed through a light-emitting diode or a lamp.

Dc input

load

S1

dc

The incident light will cause the LASCR to turn on and permit a flow of charge through the road as establish by the Dc supply. The LASCR can be turned off using the reset switch.

This system offers the additional advantage over an electromechanical switch of long life microsecond response, small size, and the elimination of contact bounce.