Deck 16: The Unijunction Transistor

Question 1

When the voltage applied to the emitter becomes about ____ volts more positive (higher) than the voltage applied to first base, the UJT turns on.

A) 5
B) 10
C) 15
D) 20

Answer 1

B

Question 2

By varying the resistance connected in series with the capacitor, the amount of time needed for charging the capacitor can be changed, thereby controlling the pulse rate of the UJT.

Answer 2

True

Question 3

The pulse rate is determined by the amount of resistance and capacitance connected to the emitter of the UJT.

Answer 3

True

Question 4

The unijunction transistor is made by combining four layers of semiconductor material.

Question 5

The unijunction transistor is tested with a(n) ____.

A) ammeter
B) voltmeter
C) oscilloscope
D) ohmmeter

Question 6

The programmable unijunction transistor can be used to phase shift an SCR.

Question 7

The formula used to calculate the time to control the pulse rate of the UJT is ____.

A) T = RC
B) R = TC
C) C = RT
D) T = RI

Question 8

The UJT has three paths through it for current flow.

Question 9

The ____ is a special device that has two bases and one emitter.

A) bijunction transistor
B) multijunction transistor
C) unijunction transistor
D) monojunction transistor

Question 10

The unijunction transistor can furnish a large output pulse, because the pulse is produced by the ____.

A) discharging capacitor
B) charging capacitor
C) transistor sink
D) reactive transformer