WorksheetsIndustrial Electronics
Total questions: 25
Worksheet time: 17mins
Which of the following is not a three terminal device?
Silicon Unilateral Switch
Silicon Bilateral Switch
Shockley Diode
Unijunction Transistor
In a silicon bilateral switch, gate terminal can be used to turn off the device.
True
False
A low power, low current device.
Silicon Controlled Rectifier
Silicon Controlled Switch
Silicon Unilateral Switch
All of the above
Common rating of Silicon Unilateral Switch and Silicon Bilateral Switch
0.3 V
0.7 V
5 V
8 V
Which is the determining factor for triggering of SUS and SBS?
Anode gate
Cathode Gate
Silicon Diode
Zener Diode
The silicon bilateral switch has the ability to provide positive and negative cycles.
True
False
Which of the following offers good temperature stability?
SCR
SUS
SBS
All of the above
The structure of UJT is very much similar to an N-channel JFET.
True
False
UJT in terms of junction's location is not symmetrical.
True
False
Equivalent Circuit of a Unijunction Transistor
Diode, one fixed resistor, one variable transistor
Diode, Two resistors (one fixed, one variable)
Base, Emitter, Collector
Anode, Cathode, Gate
Interbase resistance of a UJT is the resistance between emitter and pn junction when the emitter current is zero.
True
False
For an ideal UJT, the emitter firing potential is equivalent to the intrinsic stand-off ratio multiplied by the supply voltage.
True
False
The main advantage of UJT is that it offers negative resistance characteristics.
True
False
One application of UJT is it can amplify signal similar to conventional BJTs and FETs.
True
False
The datasheet of a certain UJT with a silicon diode gives an intrinsic standoff ratio of 0.5, determine the peak point emitter voltage if the supply is 15V.
(a)
UJT has a unique characteristics that when it is triggered, the emitter current increases regeneratively until it is limited by emitter power supply.
True
False
Which of the following is required in determining the charging period of a unijunction transistor?
Resistor connected to supply, Capacitor, Supply Voltage, Valley and Peak Voltage Values
Resistors connected to supply and emitter, Capacitor, Supply Voltage, Valley and Peak Voltage Values
Internal Resistance, Resistor connected to emitter, Valley Voltage and Peak Voltage Values
Supply Voltage and Intrinsic Stand-off Ratio
Once Programmable Unijunction Transistor is in the on state, the removal of gate voltage will turn the device off.
True
False
Determine the supply voltage for a silicon PUT if it is determined that η = 0.5, Peak Voltage= 12.3 V. (use the correct unit)
(a)
Frequency of oscillation of the device is equal to the reciprocal of the total period in _____________.
the whole duration of operation
one cycle
one positive half cycle
one negative half cycle
In PUT, the term programmable is applied because RBB, η, and VP as defined for the UJT can be controlled through the internal resistors RB1, RB2, and the supply voltage VBB.
True
False
Determine RB1 (in ohms) for a silicon PUT if it is determined that η = 0.5, Peak Voltage= 12.3 V and RB2= 1k ohms. (type in the value of the correct answer ONLY)
(a)
In a PUT, the cathode can be biased to a desired voltage with an external voltage divider, so that when the anode voltage exceeds this “programmed” level, the PUT turns on.
True
False
A UJT is operated with gate junction forward- biased while the JFET is normally operated with the emitter junction reverse-biased.
True
False
For a UJT, RB1 may vary from 5kΩ down to 50Ω for a corresponding change of IE from 50 mA to 0 mA.
True
False
