A Zener diode, having a breakdown voltage equal to 15 V, is used in a voltage regulator circuit as shown in the figure. The current through the diode is:

1. 5 mA
2. 10 mA
3. 15 mA
4. 20 mA

In the following figure, the diodes which are forward biased are:
 

(a)
(b)
(c)
(d)

1. (a), (b) and (d)
2. (c) only
3. (a) and (c)
4. (b) and (d)

Pure Si at \(500~\text{K}\) has an equal number of electron \((n_e)\) and hole\((n_h)\) concentrations of \(1.5\times10^{16}~\text{m}^{-3}\). Doping by indium increases \(n_h\) to \(4.5\times10^{22}~\text{m}^{-3}\).  The doped semiconductor is of:

The following figure shows a logic gate circuit with two inputs A and B, and the output Y. The voltage waveforms of A, B and Y are as given.
 

The logic gate is:

1. OR gate

2. AND gate

3. NAND gate

4. NOR gate

To get output \(Y = 1\) in the given circuit which of the following input will be correct?

The following table is for which logic gate?

1. AND
2. OR
3. NAND
4. NOT

The following logic gate is: 

1. AND 

2. NAND 

3. EX-OR 

4. OR 

One part of a device is connected to the negative terminal of a battery and the other part is connected to the positive terminal of a battery. If their ends are now altered, current does not flow in circuit. The device is:
1. P-N Junction
2. Transistor
3. Zener diode
4. Triode

Zener diode is used for:

1. rectification.

2. stabilisation.

3. amplification.

4. producing oscillations in an oscillator.

From the following diode circuit, which diode is in forward biased condition:

1.		2.
3.		4.