EASA Part 66 : Electronics Question4

Question Number. 38. In the diagram the relationship of the input to the output is. Option A. 180 degrees out of phase. Option B. 90 degrees out of phase. Option C. in phase.

Correct Answer is. 180 degrees out of phase. Explanation. A Common Emitter configuration inverts the signal.

Question Number. 39. The most suitable class of amplifier for a high fidelity radio transmitter is. Option A. B. Option B. C. Option C. A.

Correct Answer is. A. Explanation. Best amplifier is a Class A.

Question Number. 40. Which curve is from a Broadband amplifier?. Option A. C. Option B. A. Option C. B.

Correct Answer is. A. Explanation. NIL.

Question Number. 27. A capacitor-resistor coupled multistage amplifier lets. Option A. DC pass only. Option B. AC and DC pass to the next stage. Option C. AC pass only.

Correct Answer is. AC pass only. Explanation. A capacitor lets AC pass only.

Question Number. 24. What class of amplifier is biased at cut off?. Option A. C. Option B. B. Option C. A.

Correct Answer is. B. Explanation. NIL.

Question Number. 35. Where are decoupling capacitors used in digital circuits?. Option A. Between pins 1 & 8. Option B. Close to the positive pin. Option C. Close to the negative pin.

Correct Answer is. Close to the positive pin. Explanation. Close' is an important requirement. The capacitor has to be as close as possible to the +ve power supply pin. Answer a) could also be true assuming pin 8 to be ground, but in the real world not all pin 8's are negative, especially in DIL packages with more than 8 pins.

Question Number. 3. How is the amplifier in the diagram shown wired?. Option A. Common base. Option B. Common emitter. Option C. Common collector.

Correct Answer is. Common emitter. Explanation. NIL.

Question Number. 18. With reference to the circuit shown below, how is the transistor configured?. Option A. Common emitter. Option B. Common collector. Option C. Common base.

Correct Answer is. Common emitter. Explanation. The diagram shows a common emitter circuit.

Question Number. 21. How is a push-pull transistor arrangement connected?. Option A. Collector to collector. Option B. Emitter to emitter. Option C. Base to base.

Correct Answer is. Emitter to emitter. Explanation. A push pull amplifier is wired emitter to emitter.

Question Number. 25. When testing a transistor with an ohmmeter, what is the resistance of the emitter/collector?. Option A. Low resistance both ways. Option B. High resistance one way. Option C. High resistance both ways.

Correct Answer is. High resistance both ways. Explanation. Draw a transistor as 2 back to back diodes and work it out from there (same for PNP as NPN). Aircraft Electricity and Electronics 5th Edition Eismin Page 119.

Question Number. 48. The emitter, base and collector currents in a common emitter circuit, follow ohm's and kirchoff's law, which is. Option A. Ie = Ic - Ib. Option B. Ib = Ie + Ic. Option C. Ie = Ib + Ic.

Correct Answer is. Ie = Ib + Ic. Explanation. NIL.

Question Number. 36. A Common Collector circuit has the following characteristics. Option A. Medium Voltage Gain, High Current Gain, Non-Inverted Output. Option B. Low Voltage Gain, High Current Gain, Inverted Output. Option C. Medium Voltage Gain, Low Current Gain, Inverted Output.

Correct Answer is. Medium Voltage Gain, High Current Gain, Non-Inverted Output. Explanation. Common collector is a voltage follower, with high current gain.

Question Number. 29. Which mathematical operation is performed by a modulator amplifier?. Option A. Addition. Option B. Subtraction. Option C. Multiplication.

Correct Answer is. Multiplication. Explanation. A modulator amplifier is a basic input/output amplifier used for amplifying a signal. It 'multiplies' the input signal by the value of the gain.

Question Number. 14. In the diagram shown, what is resistor R used for?. Option A. Amplification. Option B. Bias. Option C. Stabilisation.

Correct Answer is. Stabilisation. Explanation. The resister R is used to provide thermal stabilisation to the transistor by supplying negative feedback if the quiescent point moves.

Question Number. 34. The typical bandwidth for an audio frequency amplifier is shown by line. Option A. Z. Option B. X. Option C. Y.

Correct Answer is. X. Explanation. Audio frequency is typically 15Hz - 20 kHz, so X is the closest.

Question Number. 6. Which mode of operation provides the best high frequency response? Common. Option A. emitter. Option B. base. Option C. collector.

Correct Answer is. base. Explanation. NIL.

Question Number. 4. "To decrease the voltage gain of a common emitter amplifier you would increase the resistance in the." Option A. base circuit. Option B. emitter circuit. Option C. collector circuit.

Correct Answer is. collector circuit. Explanation. Decreasing the collector resistance (RL) increases the output voltage of the transistor.

Question Number. 9. An amplifier current gain will be slightly less than 1, but its voltage gain will be high, if it is connected in the. Option A. common base configuration. Option B. common emitter configuration. Option C. common collector configuration.

Correct Answer is. common base configuration. Explanation. Only the common base configuration provides a current gain of less than 1.

Question Number. 12. An amplifier can provide both voltage gain and current gain when it is connected in the. Option A. common collector configuration. Option B. common emitter configuration. Option C. common base configuration.

Correct Answer is. common emitter configuration. Explanation. Only the common emitter configuration provides both current and voltage gain greater than 1.

Question Number. 2. A silicon bi-polar transistor with two depletion zones. Option A. operates by varying electric fields. Option B. is a voltage operated device. Option C. consists of 3 slices of semiconductor material.

Correct Answer is. consists of 3 slices of semiconductor material. Explanation. NIL.

Question Number. 13. How do you increase voltage gain of an amplifier?. Option A. decrease base circuit bias. Option B. decrease input resistance. Option C. decrease output resistance.

Correct Answer is. decrease input resistance. Explanation. Amplifier gain = feedback resistance / input resistance.

Question Number. 1. If light entering a photo transistor decreases, the current to the collector. Option A. decreases. Option B. remains the same. Option C. increases.

Correct Answer is. decreases. Explanation. NIL.

Question Number. 20. In a FET, the junction connections are called. Option A. drain, source and gate. Option B. drain, collector and junctions. Option C. base, collector and emitter.

Correct Answer is. drain, source and gate. Explanation. The leads of a FET are called drain, source and gate. Aircraft Electricity and Electronics 5th Edition Eismin Page 120.

Question Number. 22. Thermal runaway in a transistor is caused by. Option A. excessive heat causing maximum current flow. Option B. excessive heat causing minimum current flow. Option C. low heat causing minimum current flow.

Correct Answer is. excessive heat causing maximum current flow. Explanation. Thermal runaway is caused by excessive temperature creating an increase in current flow and hence an increase in temperature etc. etc..

Question Number. 46. The term ICE related to transistor in common emitter mode means. Option A. leakage current flowing between Collector and Emitter with Base open circuited. Option B. forward current between Collector and Emitter with Base connected to signal. Option C. leakage current between Collector and Emitter with Base connected to ground.

Correct Answer is. forward current between Collector and Emitter with Base connected to signal. Explanation. NIL.

Question Number. 31. Thermal runaway in a transistor refers to. Option A. high current flow when temperature decreases. Option B. low current flow when temperature increases. Option C. high current flow when temperature increases.

Correct Answer is. high current flow when temperature increases. Explanation. Thermal runaway is caused by the 'negative temperature coefficient' of semiconductors. More heat, less resistant, hence more current. More current, more heat etc. etc..

Question Number. 7. A FET when compared to a junction transistor is. Option A. low impedance. Option B. current operated. Option C. high impedance.

Correct Answer is. high impedance. Explanation. The biggest advantage of a FET is its high input impedance.

Question Number. 41. A transistor in Common Emitter mode gives. Option A. high voltage gain only. Option B. high current gain only. Option C. high power gain.

Correct Answer is. high power gain. Explanation. NIL.

Question Number. 28. An oscillator operating at its natural frequency has feedback which is. Option A. 90 degrees out of phase. Option B. 180 degrees out of phase. Option C. in-phase.

Correct Answer is. in-phase. Explanation. An oscillator provides positive in-phase feedback to switch itself over.

Question Number. 45. In an ideal voltage amplifier. Option A. input impedance must be high and output impedance low. Option B. input impedance must be low and output impedance high. Option C. input impedance must be low and output impedance low.

Correct Answer is. input impedance must be high and output impedance low. Explanation. NIL. http://www.safarix.com/0131470469/ch11lev1sec6

Question Number. 44. In an ideal current amplifier. Option A. input impedance must be low and output high. Option B. input impedance must be high and output low. Option C. both input and output impedances must be low.

Correct Answer is. input impedance must be low and output high. Explanation. NIL. http://www.safarix.com/0131470469/ch11lev1sec6

Question Number. 23. An advantage of a common emitter is. Option A. it has high power gain. Option B. it is a voltage follower. Option C. it has high voltage gain.

Correct Answer is. it has high power gain. Explanation. Common emitter configuration has a high power gain.

Question Number. 47. A common base amplifier has. Option A. high input and high output impedance. Option B. low input and high output impedance. Option C. low input and medium output impedance.

Correct Answer is. low input and high output impedance. Explanation. NIL. http://www.tpub.com/content/neets/14180/css/14180_48.htm

Question Number. 8. One characteristic of the emitter follower is. Option A. low resistance output. Option B. low current amplification. Option C. high voltage amplification.

Correct Answer is. low resistance output. Explanation. The emitter follower (common collector) has the lowest output resistance of all three configurations.

Question Number. 26. A transistor at saturation has. Option A. low resistance. Option B. zero resistance. Option C. high resistance.

Correct Answer is. low resistance. Explanation. A transistor at saturation is switched on - therefore has low resistance.

Question Number. 16. A transistor is said to be in the quiescent state when. Option A. no currents are flowing. Option B. it is unbiased. Option C. no signal is applied to the input.

Correct Answer is. no signal is applied to the input. Explanation. The quiescent state of a transistor is when DC is supplied to the base to bias the transistor. No signal is applied.

Question Number. 32. Resistors and capacitors are used to couple stages of amplifiers so that. Option A. only DC can be applied. Option B. only AC can be applied. Option C. equal amounts of AC and DC can be applied.

Correct Answer is. only AC can be applied. Explanation. NIL.

Question Number. 5. The current I/P and O/P waveforms in a common emitter amplifier are. Option A. out of phase. Option B. in phase. Option C. 90° out of phase.

Correct Answer is. out of phase. Explanation. NIL.

Question Number. 15. The input and output signals of a common emitter amplifier are. Option A. in phase. Option B. equal. Option C. out of phase.

Correct Answer is. out of phase. Explanation. The common emitter amplifier is the only configuration which provides an output which is anti-phase with the input.

Question Number. 43. In a differential amplifier the term 'common mode voltage' means. Option A. output voltage with one input connected to common ground. Option B. output voltage with non-inverting input at 0 volts. Option C. output voltage when both inputs have equal voltages.

Correct Answer is. output voltage when both inputs have equal voltages. Explanation. NIL.

Question Number. 19. In the circuit diagram shown, R1 and R2 are used to. Option A. set the transistor gain. Option B. increase the base voltage. Option C. set the DC bias level.

Correct Answer is. set the DC bias level. Explanation. The resistors R1 and R2 are to set the bias level of the transistor, i.e. to put the transistor into quiescence.

Question Number. 37. In a Common Emitter Amplifier RE is used for. Option A. load control. Option B. biasing. Option C. stabilisation.

Correct Answer is. stabilisation. Explanation. The emitter resistor is a stabilizing resistor.

Question Number. 17. A common base transistor circuit is so called because. Option A. the base is common to the emitter and collector circuits. Option B. the base region is located between the emitter and collector region. Option C. the base is n-type material.

Correct Answer is. the base is common to the emitter and collector circuits. Explanation. NIL.

Question Number. 42. For a transistor in common emitter mode, the term Hfe indicates. Option A. the Voltage gain Vce/Vbe at Ib constant. Option B. the Power gain Pin/Pout. Option C. the current gain Ic/Ib at Vce constant.

Correct Answer is. the current gain Ic/Ib at Vce constant. Explanation. NIL. http://www.vishay.com/brands/measurements_group/guide/glossary/commodvt.htm

Question Number. 10. The common collector amplifier is sometimes called the emitter follower circuit because. Option A. the emitter voltage follows the collector voltage. Option B. the emitter current follows the collector current. Option C. the emitter voltage follows the base voltage.

Correct Answer is. the emitter voltage follows the base voltage. Explanation. NIL.

Question Number. 33. An advantage of a FET when compared to a bi-polar transistor is. Option A. the switching time is quicker. Option B. the input resistance is higher. Option C. the input resistance is lower.

Correct Answer is. the input resistance is higher. Explanation. A FET has a high input resistance and a low output resistance.

Question Number. 11. Amplifiers may be classified as. Option A. voltage amplifiers or power amplifiers. Option B. voltage amplifiers or impedance amplifiers. Option C. common emitter or common collector amplifiers.

Correct Answer is. voltage amplifiers or power amplifiers. Explanation. Amplifiers are classified as either voltage or power amplifiers.

Question Number. 30. A JFET is. Option A. either of the above depending on resistance in the circuit. Option B. current sensitive. Option C. voltage sensitive.

Correct Answer is. voltage sensitive. Explanation. A JFET is voltage sensitive, whereas a normal transistor is current sensitive. Aircraft Electricity and Electronics 5th Edition Eismin Page 119.