In a common emitter transistor amplifier, the audio signal voltage across resistance of 1 k is 2V. If the base resistance is 200 and the current amplification factor is 50, the input signal voltage will be
(1) 4 mV
(2) 8 mV
(3) 16 mV
(4) 32 mV
The input resistance of a silicon transistor is
100 . Base current is changed by 40
which results in a change in collector current
by 2 mA. This transistor is used as a common-
emitter amplifier with a load resistance of 4 k.
The voltage gain of the amplifier is
1. 2000
2. 3000
3. 4000
4. 1000
The device that can act as a complete electronic circuit is
1. Junction diode
2. Integrated circuit
3. Junction transistor
4. Zener diode
For transistor action:
(a) | the base, emitter and collector regions should have similar size and doping concentrations. |
(b) | the base regions must be very thin and lightly doped. |
(c) | the emitter-base junction is forward biased and the base-collector junction is reverse biased. |
(d) | both the emitter-base junction as well as the base-collector junction are forward biased. |
Which of the following pairs of statements is correct?
1. (d) and (a)
2. (a) and (b)
3. (b) and (c)
4. (c) and (d)
A transistor is operated in common-emitter configuration at such that a change in the base current from 100 to 200 produces a change in the collector current from 5 mA to 10 mA. The current gain is
1. 75 2. 100
3. 150 4. 50
The emitter-base junction of a transistor is …… biased while the collector-base junction is ……. biased.
1. reverse, forward
2. reverse, reverse
3. forward, forward
4. forward, reverse
In an NPN transistor the collector current is 24 mA. If 80% of electrons reach collector its base current in mA is
1. 36 2. 26
3. 16 4. 6
If = 0.98 and current through emitter = 20 mA, the value of is
(a) 4.9 (b) 49
(c) 96 (d) 9.6
If , , are the lengths of the emitter, base and collector of a transistor then
(1)= =
(2) <>
(3) < <
(4) > >