Chapter - 2 (Multiple Choice)
The forward voltage across a conducting silicon diode is about 0.3 V. 1.7 V. -0.7 V. 0.7 V.
0.7 V.
If the ac supply is 50 Hz, what will be the ripple frequency out of the full-wave rectifier? 50 Hz 60 Hz 100 Hz 120 Hz
100 Hz
A silicon diode is forward-biased. You measure the voltage to ground from the anode at _____, and the voltage from the cathode to ground at _____. 0 V, 0.3 V 2.3 V, 1.6 V 1.6 V, 2.3 V 0.3 V, 0 V
2.3 V, 1.6 V
What is the PIV for each diode in a full-wave center-tapped rectifier? Note: Vp(out) = peak output voltage. Vp(out) - 0.7 V Vp(out) + 0.7 V 2Vp(out) - 0.7 V 2Vp(out) + 0.7 V
2Vp(out) + 0.7 V
How many terminals do the 7800 series fixed positive voltage regulators have? 2 3 4 5 none of the above
3
What is the VRRM (PIV rating) for the 1N4001 rectifier diode? 50 V 100 V 200 V 400 V none of the above
50 V
If the ac supply is 60 Hz, what will be the ripple frequency out of the half-wave rectifier? 30 Hz 50 Hz 60 Hz 120 Hz
60 Hz
You have an unknown type of diode in a circuit. You measure the voltage across it and find it to be 0.3 V. The diode might be a silicon diode. a germanium diode. a forward-biased silicon diode. a reverse-biased germanium diode.
a germanium diode.
The wide end on a schematic indicates the __________ of a diode. ground direction of electron flow cathode anode
anode
A reverse-biased diode has the _____ connected to the positive side of the source, and the _____ connected to the negative side of the source. cathode, anode cathode, base base, anode anode, cathode
cathode, anode
What type of diode circuit is used to add or restore a dc level to an electrical signal? clipper or limiter clamper IC voltage regulator none of the above
clamper
What type of diode circuit is used to clip off portions of signal voltages above or below certain levels? clipper or limiter clamper IC voltage regulator none of the above
clipper or limiter
For a forward-biased diode, the barrier potential _____ as temperature increases. decreases remains constant increases
decreases
As the forward current through a silicon diode increases, the internal resistance increases. decreases. remains the same.
decreases.
The output frequency of a half-wave rectifier is _____ the input frequency. one-half twice equal to none of the above
equal to
Each diode in a center-tapped full-wave rectifier is _____ -biased and conducts for _____ of the input cycle. forward, 90º reverse, 180º forward, 180º reverse, 90º
forward, 180º
A silicon diode has a voltage to ground of -117 V from the anode. The voltage to ground from the cathode is -117.7 V. The diode is open. shorted. forward-biased. reverse-biased.
forward-biased.
Under normal conditions a diode conducts current when it is reverse-biased. forward-biased. avalanched. saturated.
forward-biased.
For a forward-biased diode, as temperature is _____, the forward current _____ for a given value of forward voltage. decreased, increases increased, increases increased, decreases decreased, decreases
increased, increases
In the operation of a half-wave rectifier with a capacitor-input filter, the ripple factor can be lowered by _____ the value of the filter capacitor or _____ the load resistors. decreasing, decreasing decreasing, increasing increasing, decreasing increasing, increasing
increasing, increasing
As the forward current through a silicon diode increases, the voltage across the diode increases to a 0.7 V maximum. decreases. is relatively constant. decreases and then increases.
is relatively constant.
Reverse breakdown is a condition in which a diode is subjected to a large reverse voltage. is reverse-biased and there is a small leakage current. has no current flowing at all. is heated up by large amounts of current in the forward direction.
is subjected to a large reverse voltage.
In a regulated supply, what term describes how much change occurs in the output voltage for a given change in the input voltage? load regulation voltage regulator line regulation ripple voltage
line regulation
In a regulated supply, what term describes how much change occurs in the output voltage over a certain range of load current values, from minimum to maximum current? line regulation voltage regulator current regulator load regulation
load regulation
he most common type of diode failure is a(n) _____. open short resistive
open
An ideal diode presents a(n) _____ when reversed-biased and a(n) _____ when forward-biased. open, short short, open open, open short, short
open, short
PIV is which of the following? peak input voltage peak inverse voltage peak immediate voltage positive input voltage
peak inverse voltage
A silicon diode in a half-wave rectifier has a barrier potential of 0.7 V. This has the effect of reducing the peak output voltage by 0.7 V. increasing the peak output voltage by 0.7 V. reducing the peak input voltage by 0.7 V. no effect.
reducing the peak output voltage by 0.7 V.
There is a small amount of current across the barrier of a reverse-biased diode. This current is called forward-bias current. reverse breakdown current. conventional current. reverse leakage current.
reverse leakage current.
A silicon diode measures a low value of resistance with the meter leads in both positions. The trouble, if any, is the diode is open. the diode is shorted to ground. the diode is internally shorted. the diode is working correctly.
the diode is internally shorted.
The term bias in electronics usually means the value of ac voltage in the signal. the condition of current through a pn junction. the value of dc voltages for the device to operate properly. the status of the diode.
the value of dc voltages for the device to operate properly.
The output frequency of a full-wave rectifier is _____ the input frequency. one-half equal to twice one-quarter
twice
