Semiconductors

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1. Examples of semiconductor materials are: a) aluminium and steel b) brass and zinc c) quartz and silica d) silicon and germanium.

2. The component shown below is: a) a signal diode b) a bridge rectifier c) a zener diode regulator d) a miniature transformer.

3. A perfect diode would have: a) zero forward resistance and zero reverse resistance b) zero reverse resistance and infinite forward resistance c) zero forward resistance and infinite reverse resistance d) infinite forward resistance and infinite reverse resistance.

4. When a bipolar junction transistor is used as a conventional amplifer: a) both the base-emitter and collector-base junctions are forward biased b) both the base-emitter and collector-base junctions are reverse biased c) the base-emitter is forward biased whilst the collector-base is reverse biased d) the base-emitter is reverse biased whilst the collector-base is forward biased.

5. The forward voltage drop for germanium diode is approximately: a) 0.2 V b) 0.5 V c) 0.6 V d) 0.8 V.

6. The typical operating forward current for a standard LED is: a) 15 mA b) 150 mA c) 300 mA d) 1 A.

7. The connections to a silicon controlled rectifier are labelled: a) anode, cathode, base b) anode, cathode, gate c) anode, cathode, emitter d) anode, cathode, trigger.

8. In the diagram of the rectifier shown below, which connection is the positive output terminal? a) A b) B c) C d) D.

9. An application for a zener diode is: a) a rectifier b) a current limiter c) a power indicator d) a voltage regulator.

10. The component shown below is: a) a zener diode b) a signal diode c) a variable capacitance diode d) a silicon controlled rectifier.

11. The component shown below is: a) a zener diode b) a signal diode c) a variable capacitance diode d) a silicon controlled rectifier.

12. The connection marked X in the diagram below is: a) base b) emitter c) gate d) source.