In a PN-junction diode:
1. | the current in the reverse biased condition is generally very small. |
2. | the current in the reverse biased condition is small but the forward-biased current is independent of the bias voltage. |
3. | the reverse-biased current is strongly dependent on the applied bias voltage. |
4. | the forward-biased current is very small in comparison to reverse-biased current. |
The electrical circuit used to get smooth output from a rectifier circuit is called:
1. oscillator.
2. filter.
3. amplifier.
4. logic gates.
Two PN-junctions can be connected in series by three different methods as shown in the figure. If the potential difference in the junctions is the same, then the correct connections will be:
1. | In the circuit (1) and (2) |
2. | In the circuit (2) and (3) |
3. | In the circuit (1) and (3) |
4. | Only in the circuit (1) |
The correct symbol for zener diode is:
1. | 2. | ||
3. | 4. |
Which of the following logic gate is a universal gate?
1. OR
2. NOT
3. AND
4. NOR
How much is the forbidden gap (approximately) in the energy bands of germanium at room temperature?
1. \(1.1~\text{eV}\)
2. \(0.1~\text{eV}\)
3. \(0.67~\text{eV}\)
4. \(6.7~\text{eV}\)
In a good conductor, the energy gap between the conduction band and the valence band is
1. Infinite
2. Wide
3. Narrow
4. Zero
A Ge specimen is doped with Al. The concentration of acceptor atoms is . Given that the intrinsic concentration of electron hole pairs is , the concentration of electrons in the specimen is:
1. | \(10^{17} / \mathrm{m}^3 \) | 2. | \(10^{15} / \mathrm{m}^3 \) |
3. | \(10^4 / \mathrm{m}^3 \) | 4. | \(10^2 / \mathrm{m}^3\) |
In a semiconducting material, the mobilities of electrons and holes are and respectively. Which of the following is true?
1. \(\mu_{e} > \mu _{h}\)
2. \(\mu_{e} < \mu _{h}\)
3. \(\mu_{e} = \mu _{h}\)
4. \(\mu_{e} <0; ~\mu _{h}>0\)
The diode used in the circuit shown in the figure has a constant voltage drop of 0.5 V at all currents and a maximum power rating of 100 milliwatts. What should be the value of the resistor R, connected in series with the diode for obtaining maximum current?
1. 1.5
2. 5
3. 6.67
4. 200