Title: Electronics Theory Final
Course: Electronics Theory (IC 102-IC 102) > Section: Assessments

Q: Silicon doped with impurities are used in the manufacture of semiconductor devices.
- True
- False
A: True

Q: A good op - amp has high voltage gain, low output impedance, and high input impedance.
- True
- False
A: True

Q: An op - amp comparator has an output dependent upon the polarities of the two inputs.
- True
- False
A: True

Q: The larger the ripple voltage, the better the filter.
- True
- False
A: False

Q: A BJT transistor has the base - emitter junction reverse - biased for proper operation.
- True
- False
A: False

Q: When a transistor is checked out - of - circuit, a very low resistance reading should be obtained between the C and E leads of a good transistor.
- True
- False
A: False

Q: A common - emitter amplifier has very high input impedance, high voltage gain, and high current gain.
- True
- False
A: False

Q: A common - base amplifier has a high current gain.
- True
- False
A: False

Q: The SCR is a device that can be triggered "on" by a pulse applied to the gate.
- True
- False
A: True

Q: The forced commutation method requires momentarily forcing current in the direction opposite to the reverse conduction so that the net reverse current is reduced below the holding value.
- True
- False
A: False

Q: The differential amplifier is used as the input stage of an operational amplifier.
- True
- False
A: True

Q: The application of a DC voltage to control diode conduction is called
- oscillation
- amplification
- bias
- a PN junction
A: oscillation

Q: A DMM measures 0.13 Ohms in both directions when testing a diode. The diode is
- constructed of Silicon and is good.
- shorted.
- operating normally.
- open.
A: constructed of Silicon and is good.

Q: Refer to (c) in the figure above. This rectifier arrangement
- will produce a negative output voltage.
- will produce a positive output voltage.
- is incorrectly connected.
- A or C above.
A: will produce a negative output voltage.

Q: Refer to the figure above. As long as the zener is in regulation
- there is no current through RL.
- there is no current through the zener.
- VRL will be equal to 0.7V.
- the current (IR) remains constant.
A: there is no current through RL.

Q: A varactor is a diode that
- varies its resistance with temperature.
- changes its capacitance with voltage.
- emits light when forward biased.
- switches very fast.
- exhibits an increase in reverse current with light intensity.
A: varies its resistance with temperature.

Q: The correct way to illuminate an LED is to
- place the LED in series with a resistor and a 5 V dc supply with the anode toward the positive side of the supply.
- place the LED in forward bias directly across a 5 V dc supply.
- place the LED in reverse bias directly across a 5 V dc supply.
- place the LED in series with a resisitor and a 5 V dc supply with the cathode toward the positive side of the supply.
A: place the LED in series with a resistor and a 5 V dc supply with the anode toward the positive side of the supply.

Q: If the load resistance decreases in a zener regulator, the zener current
- equals the source voltage divided by the series resistance.
- decreases.
- increases.
- stays the same.
A: equals the source voltage divided by the series resistance.

Q: Refer to the figure above. The value of IB is
- 8.6 mA.
- 860microA.
- 0.7microA.
- 1 mA.
A: 8.6 mA.

Q: A BJT has an IB of 75micro A and a Beta(dc) of 100. The value of IC is
- 10 mA.
- 75 mA.
- 7.5 mA.
- 175microA.
A: 10 mA.

Q: Refer to the figure above. The value of IC at cutoff is
- 2.13 mA.
- 0 mA.
- 10.65microA.
- 10 mA.
A: 2.13 mA.

Q: In a bipolar junction transistor, collector current is controlled by
- base current.
- collector voltage.
- collector resistance.
- All of the above.
A: base current.

Q: Saturation and cutoff are operating conditions that are very useful when operating the transistor as
- a current amplifier.
- a linear amplifier.
- a switch.
- None of the above.
A: a current amplifier.

Q: Refer to (c) in the figure above. The most probable cause of trouble, if any, from these voltage
measurements is
- RE is open.
- the base emitter junction is open.
- a short from collector to emitter.
- There are no problems.
A: RE is open.

Q: The most suitable biasing technique used is the
- base-bias.
- voltage-divider bias.
- emitter-bias.
- collector-bias.
A: base-bias.

Q: Voltage - divider bias provides
- a stable Q-point.
- an unstable Q-point.
- a Q-point that easily varies with changes in the transistors current gain.
- Both A and C above.
A: a stable Q-point.

Q: If the base - emitter junction opens in a voltage - divider biased circuit, the emitter voltage will measure
- 0.7 V less than the base.
- a voltage nearly equal to VCC.
- 0.7 V more than the base.
- 0 V.
A: 0.7 V less than the base.

Q: The main difference between an NPN and PNP transistor amplifier is that
- PNP transistors need more heat sinking.
- PNP transistors require opposite bias polarities as compared to NPN.
- PNP transistors cannot amplify sine waves.
- NPN transistors are linear amplifiers, while PNP amplifiers are nonlinear.
A: PNP transistors need more heat sinking.

Q: Refer to the figure above. The value of VC is
- 0 V.
- 20V.
- 10 V.
- 5 V.
A: 0 V.

Q: Refer to the figure above. If RC opened, VE would
- remain the same.
- decrease.
- increase.
- be undetermined.
A: remain the same.

Q: Refer to the figure above. If the emitter collector shorted, the voltage VC would be
- 3.33 V.
- 0 V.
- 16.67 V.
- 20 V.
A: 3.33 V.

Q: Which of the following is not a characteristic of the emitter - follower?
- Voltage gain of 1
- Low output impedance
- Low input impedance
- High current gain
A: Voltage gain of 1

Q: A triac is used for ac because
- it is turned off when the ac voltage reaches zero.
- it can deliver more power to the load in a cycle.
- it conducts on both alternations.
- All of the above.
A: it is turned off when the ac voltage reaches zero.

Q: The only way to stop an SCR that is conducting is by
- breakover.
- reverse-bias triggering.
- a positive trigger.
- low-current drop out.
A: breakover.

Q: A UJT has
- two base leads.
- one emitter lead.
- two emitter and one base leads.
- both A and B above.
A: two base leads.

Q: A triac
- can trigger only on negative gate voltages.
- can trigger only on positive gate voltages.
- cannot be triggered with gate voltages.
- can be triggered by either a positive or a negative gate voltage.
A: can trigger only on negative gate voltages.

Q: Refer to the figure above. Which circuit is the inverting amplifier?
- (a)
- (b)
- (c)
- None of the above.
A: (a)

Q: Refer to the figure above. Which circuit has a voltage gain of 10?
- (a)
- (b)
- (c)
- None of the above.
A: (a)

Q: Refer to (a) in the figure above. If this circuit has a Vin = 12 Vp - p, the value of Vout would be
- -20 V.
- 20 V.
- 8.48 Vp-p.
- 12 Vp-p.
A: -20 V.

Q: Refer to (c) in the figure above. Vin = - 60 mV. The value of Vout is
- about 16 V.
- 600 mV.
- 660 mV.
- -600 mV.
A: about 16 V.

Q: A voltage follower amplifier comes to you for service. With a sine wave input of 1 V, the output is squared off at approximately 30 V peak - to - peak. The most likely problem is
- open feedback loop.
- the input is shorted to ground.
- the output is shorted to ground.
- no dc supply voltage.
A: open feedback loop.

Q: The op - amp can amplify
- dc signals only.
- ac signals only.
- both ac and dc signals.
- neither ac nor dc signals.
A: dc signals only.

Q: The open - loop voltage gain (Aol) of an op - amp is the
- most controlled parameter.
- same as Acm.
- external voltage gain the device is capable of.
- internal voltage gain the device is capable of.
A: most controlled parameter.

Q: With negative feedback, the returning signal
- is proportional to differential voltage gain.
- is proportional to output current.
- aids the input signal.
- opposes the input signal.
A: is proportional to differential voltage gain.

Q: The voltage follower has a
- closed-loop voltage gain of unity.
- closed-loop bandwidth of zero.
- small open-loop voltage gain.
- large closed-loop output impedance.
A: closed-loop voltage gain of unity.

Q: Refer to (c) in the figure above. With the inputs shown, the output voltage would be
- -Vsat.
- 7 V.
- +Vsat.
- -7 V.
A: -Vsat.

Q: Refer to the figure above. In servicing this power supply, you notice that the ripple voltage is higher than normal and that the ripple frequency has changed to 60 Hz. The probable trouble is that
- a diode has shorted.
- the filter capacitor has opened.
- a diode has opened.
- the inductor has opened.
A: a diode has shorted.

Q: A diode is operated in reverse bias.  As the reverse voltage is decreased, the depletion region
- narrows.
- has a constant width.
- widens.
- is not related to reverse voltage.
A: narrows.

Q: A typical use for an optical coupler might be to
- connect telephone lines to electronic equipment.
- transfer signals to a fiber optic cable.
- isolate one circuit from another.
- all of the above
A: connect telephone lines to electronic equipment.

Q: Refer to the above picture.  If R1 = 10K ohms, the DC voltage present at the base of this silicon transistor is
- 0.7V
- 9.3V
- 10V
- 20V
A: 0.7V