Explain why elemental semiconductor can not be used to make visible LEDs.

2

(a)

In normal case, emitter-base junction is the forward bias and collector-base junction is reverse biased. What will happen if emitter is reverse biased and collector is forward biased?

2

(a)

If the resistance R₁ is increased (see figure), how will the reading of the ammeter and voltmeter change?

2

(a)

Write the truth for the circuit shown in figure below. Name the gate that the circuit resembles.

2

(a)

A Zener of power rating 1 W is to be used as a voltage regulator. If Zener has a breakdown of 5 V and it has to regulate voltage which fluctuated between 3 V and 7 V, what should be the value of R_S for safe operations as shown below figure?
   

2

(a)