Electronics

Question 1

One advantage of a UJT over a diac is that the break-over voltage can be adjusted (T or F)

Answer 1

True

Question 2

In order for a Triac to conduct, a small trigger current must be applied to its base (T or F)

Answer 2

False

Question 3

P-type semiconductor material is silicon that has been doped with a pentavalent impurity (t or f)

Answer 3

False

Question 4

An SCR is considered a uni-directional thyristor device (T or F)

Answer 4

True

Question 5

An electrostatic damage (ESD) incident with a sensitive component will most often cause what ?

Answer 5

Latent damage to component

Question 6

For the Diac speciality thyristor what statement is correct

Answer 6

A diac can operate in AC or DC circuit

Question 7

The 3 leads of an IGBT are identifies as

Answer 7

Collector, Gate, Emitter

Question 8

An SCR that has been triggered can be turned off by doing what

Answer 8

Placing a short circuit between anode and cathode

Question 9

A unijunction transistor will start conducting when

Answer 9

Base 1 is made negative with respect to the emitter

Question 10

A Bipolar junction transistor (BJT) operating only at saturation and only at cutoff can be compared to what

Answer 10

A switch

Question 11

A diode is forward biased when

Answer 11

Cathode is connected to neg of source

Question 12

When will a depletion type MOSFET have an increase in source to drain current

Answer 12

As gate voltage is reduced

Question 13

A resistance-capacitance triggering circuit will fire the SCR gate from 0deg to what angle

Answer 13

180deg

Question 14

A diac is often used for what purpose

Answer 14

Triggering Triacs

Question 15

Which must happen for the correct operation of a NPN Bipolar Junction Transistor

Answer 15

The base - emitter junction must be forward biased

Question 16

Which logic gate conforms to the statement “output is low only if all inputs are high”

Answer 16

NAND

Question 17

Triacs are NOT typically used in which one of the following circuits

Answer 17

Rectifiers

Question 18

A resistance-capacitance triggering circuit will fire the SCR gate from 0deg to what angle

Answer 18

180deg

Question 19

Regardless of what type of triggering using, an SCR will always block for at least 180deg of a cycle when connected to an AC source (t or f)

Answer 19

True

Question 20

The main difference between SCR’s and TRIAC’s is that TRIAC’s do not have a gate terminal (t or f)

Answer 20

False

Question 21

An SCR has a resistance- capacitance trigger circuit. It is modified by adding a second capacitor in parallel to the first capacitor. What will happen to the SCR’s conduction angle?

Answer 21

It will decrease

Question 22

An IGBT can be turned ‘On’ by

Answer 22

Applying a positive input voltage signal across the gate and emitter

Question 23

A common use for injunction transistors is as

Answer 23

As a relaxation oscillator to fire Traic’s and SCR’s

Question 24

For a (bjt) transistor that is not saturated, an increase in base current (ib) would result in what?

Answer 24

Decrease in VCE

Question 25

To turn on the SCR, what must the polarity of the gate with respect to the cathode

Answer 25

Gate must be positive with respect to the cathode

Question 26

A diac will only conduct when

Answer 26

The applied voltage exceeds the breakover voltage