AE TEST

______ is a component that transfers electrical signals between two isolated circuits by using light.

• optocoupler

• phototransistor

• LED

• photodiode

An opto-isolator contains: (i) LED (ii) photosensor

• Only (i)

• Only (ii)

• Both (i) & (ii)

• None of the above

Solar cell works on the principle of

• Photo emissivity

• Photo emissivity

• Photo voltaic effect

• photoelectric effect

In solar cell ______ varies when exposed to light

• current

• voltage

• resistance

• All of the above

Most of the electrons in the base of an NPN transistor flow:

• out of the base lead

• into the collectorinto the emitter

• into the emitter

• into the base supply 

In a transistor, collector current is controlled by:

• collector voltage

• base current

• collector resistance

• all of the above 

A heat sink is generally used with a  transistor to __________

• Increase the forward current

• Decrease the forward current

• Compensate for excessive doping

• Prevent excessive temperature rise

A transistor converts.............

• D.C Power into a.c. power

• a.c. power into d.c. power

• high resistance into low resistance

• square

A transistor has _____ regions

• 1

• 2

• 3

• 4

In transistor, the function of the emitter is to

• inject electrons or holes

• collecting or gathering electrons or holes

• pass electrons or holes on to the collector directly

• Both a & b