15. Power electronics essentially deals with control of a.c. power at
A. frequencies above 20 kHz
B. frequencies above 1000 kHz
C. frequencies less than 10 Hz
D. 50 Hz frequency
16. When the emitter terminal of a UJT is open, the resistance between the base terminals is generally
A. high
B. low
C. extermely low
D. none of the above
17. When a UJT is turned ON, the resistance between emitter terminal and lower base terminal
A. remains the same
B. is decreased
C. is increased
D. none of the above
18. To turn on UJT, the forward bias on the emitter dioile should be _____ the peak point voltage.
A. less then
B. equal to
C. more than
D. none of the above
19. A UJT is sometimes called __ diode.
A. low resistance
B. high resistance
C. single-base
D. double-based '
20. When the temperature increases, the interbase resistance (RBB) of a UJT
A. increases
B. decreases
C. remains the same
D. none of the above
21. When the temperature increases, the intrinsic stand off ratio
A. increases
B. decreases
C. essentially remains the same
D. none of the above
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