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Semiconductors Practice Test

based on 1 rating
By — McGraw-Hill Professional
Updated on Apr 25, 2014

Review the following concepts if needed:

Semiconductors Practice Test

A good score is eight correct. Answers are given at the end.

1. A JFET biased beyond pinchoff can work as

(a) a power amplifier.

(b) a solar panel.

(c) an injection laser.

(d) none of the above.

 

2. As the depletion region in a JFET becomes wider,

(a) the channel capacitance increases.

(b) the channel capacitance decreases.

(c) the channel conducts less current.

(d) the channel conducts more current.

 

3. Fill in the blank in the following sentence to make it true. “The____ in a bipolar transistor is the frequency at which the current gain becomes equal to unity in a grounded-emitter circuit.”

(a) forward breakover

(b) junction capacitance

(c) alpha cutoff

(d) gain bandwidth product

 

4. A bipolar transistor has a current gain, under ideal conditions, of 16.0 at an operating frequency of 1,000 Hz. The alpha cutoff is specified as 600 kHz. What is the maximum possible current gain that the device can have at 75 MHz?

(a) 11.3

(b) 16.0

(c) 22.6

(d) It cannot be determined from this information.

 

5. At the p-n junction in a diode that is conducting in the forward direction,

(a) the n -type semiconductor is always saturated.

(b) the majority carriers are electrons.

(c) the p -type material is positively charged relative to the n -type material.

(d) the collector is positively charged relative to the base.

 

6. An enhancement-mode device

(a) conducts well at zero bias.

(b) amplifies best when the p-n junction is in saturation.

(c) can be replaced with a depletion-mode device if the polarity is reversed.

(d) does none of the above.

 

7. Six silicon diodes, each with a forward breakover voltage of 0.60 V, are connected in parallel, with their p-n junctions all oriented the same way. What is the forward breakover voltage of the combination?

(a) 0.60 V

(b) 0.10 V

(c) 3.60 V

(d) It cannot be determined from this information.

 

8. The path between the source and drain of a JFET

(a) always conducts.

(b) is called the channel.

(c) is called the depletion region.

(d) never conducts.

 

9. A pnp transistor can act as a current amplifier when

(a) small changes in the base current produce large changes in the collector current.

(b) small changes in the collector voltage produce large changes in the base voltage.

(c) small changes in the source current produce large changes in the gate current.

(d) small changes in the gate voltage produce large changes in the drain current.

 

10. When a p-n junction in a bipolar transistor is reverse-biased and the voltage is increased indefinitely, the junction eventually will

(a) act like an inductor.

(b) amplify.

(c) act like a resistor.

(d) conduct.

 

Answers

1. a

2. c

3. d

4. d

5. c

6. d

7. a

8. b

9. a

10. d

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