Electronics Flashcards
One advantage of a UJT over a diac is that the break-over voltage can be adjusted (T or F)
True
In order for a Triac to conduct, a small trigger current must be applied to its base (T or F)
False
P-type semiconductor material is silicon that has been doped with a pentavalent impurity (t or f)
False
An SCR is considered a uni-directional thyristor device (T or F)
True
An electrostatic damage (ESD) incident with a sensitive component will most often cause what ?
Latent damage to component
For the Diac speciality thyristor what statement is correct
A diac can operate in AC or DC circuit
The 3 leads of an IGBT are identifies as
Collector, Gate, Emitter
An SCR that has been triggered can be turned off by doing what
Placing a short circuit between anode and cathode
A unijunction transistor will start conducting when
Base 1 is made negative with respect to the emitter
A Bipolar junction transistor (BJT) operating only at saturation and only at cutoff can be compared to what
A switch
A diode is forward biased when
Cathode is connected to neg of source
When will a depletion type MOSFET have an increase in source to drain current
As gate voltage is reduced
A resistance-capacitance triggering circuit will fire the SCR gate from 0deg to what angle
180deg
A diac is often used for what purpose
Triggering Triacs
Which must happen for the correct operation of a NPN Bipolar Junction Transistor
The base - emitter junction must be forward biased
Which logic gate conforms to the statement “output is low only if all inputs are high”
NAND
Triacs are NOT typically used in which one of the following circuits
Rectifiers
A resistance-capacitance triggering circuit will fire the SCR gate from 0deg to what angle
180deg
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)
True
The main difference between SCR’s and TRIAC’s is that TRIAC’s do not have a gate terminal (t or f)
False
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?
It will decrease
An IGBT can be turned ‘On’ by
Applying a positive input voltage signal across the gate and emitter
A common use for injunction transistors is as
As a relaxation oscillator to fire Traic’s and SCR’s
For a (bjt) transistor that is not saturated, an increase in base current (ib) would result in what?
Decrease in VCE
To turn on the SCR, what must the polarity of the gate with respect to the cathode
Gate must be positive with respect to the cathode
A diac will only conduct when
The applied voltage exceeds the breakover voltage
