Q.1

In a power supply diagram, which block indicates a pulsating dc output?

  • transformer
  • filter
  • rectifier
  • regulator
Q.2

Since diodes are destroyed by excessive current, circuits must have:

  • higher voltage sources
  • current limiting resistors
  • more dopants
  • higher current sources
Q.3

Providing a constant output regardless of ac input or load resistance changes is the function of a:

  • transformer
  • filter
  • regulator
  • rectifier
Q.4

When a diode is forward biased, the voltage across it

  • is directly proportional to the current
  • is inversely proportional to the current
  • is directly proportional to the source voltage
  • remains approximately the same
Q.5

Which of the following circuits would require the least amount of filtering?

  • A half-wave rectifier
  • A full-wave rectifier
  • A bridge rectifier
  • A full-wave rectifier and a bridge rectifier
Q.6

With a 12 V supply, a silicon diode, and a 370-ohm resistor in series, what voltage will be dropped across the diode?

  • 0.3 V
  • 0.7 V
  • 0.9 V
  • 1.4 V
Q.7

Shunting the ac component away from the load is the task of a:

  • transformer
  • filter
  • regulator
  • rectifier
Q.8

List three diode packages:

  • clip package, DIP, small current package
  • DIP, small current package, large current package
  • small current package, large current package, and SIP
  • small current package, large current package, clip package
Q.9

A diode for which you can change the reverse bias, and thus vary the capacitance is called a

  • varactor diode
  • tunnel diode
  • zener diode
  • switching diode
Q.10

A filtered full-wave rectifier voltage has a smaller ripple than does a half-wave rectifier voltage for the same load resistance and capacitor values because:

  • there is a shorter time between peaks
  • there is a longer time between peaks
  • the larger the ripple, the better the filtering action
  • none of the above
Q.11

When a diode is destroyed it has infinite impedance. When damaged by heat it will probably:

  • short
  • conduct more
  • conduct less
  • open
Q.12

The characteristic curve for the complex model of a silicon diode shows that

  • the barrier potential is 0 V
  • the barrier potential stays fixed at 0.7 V
  • the barrier potential increases slightly with an increase in current
  • the barrier potential decreases slightly with an increase in current
Q.13

Why is heat produced in a diode?

  • due to current passing through the diode
  • due to voltage across the diode
  • due to the power rating of the diode
  • due to the PN junction of the diode
Q.14

The arrow in the schematic symbol of a diode points to

  • the n-type material, which is called the anode
  • the n-type material, which is called the cathode
  • the p-type material, which is called the anode
  • the p-type material, which is called the cathode
Q.15

What is a varistor?

  • a voltage-dependent resistor
  • a voltage-dependent diode
  • a current-dependent resistor
  • a current-dependent diode
Q.16

An LED can be tested with an ohmmeter.

  • True
  • False
Q.17

A rectifying diode can change ac voltage to dc voltage.

  • True
  • False
Q.18

fbq16_1001_1.gif
Atoms in a silicon crystal are held together by ___ bonds.

  • crystal
  • chemical
  • electrical
  • covalent
Q.19

If the frequency of the applied ac signal to a half-wave rectifier is 60 Hz, the frequency of the pulsating dc output will be

  • 30 pps
  • 60 pps
  • 90 pps
  • 120 pps
Q.20

A pn junction allows current flow when

  • the p-type material is more positive than the n-type material
  • the n-type material is more positive than the p-type material
  • both the n-type and p-type materials have the same potential
  • there is no potential on the n-type or p-type materials
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