11. A UJT has ……………………
(a) two pnjunctions
(b) one pnjunction
(c) three pnjunctions
(d) none of the above
12. The normal way to turn on a diac is by …………
(a) gate current
(b) gate voltage
(c) breakover voltage
(d) none of the above
13. A diac is ………… switch.
(a) an a.c.
(b) a d.c.
(c) a mechanical
(d) none of the above
14. In a UJT,the p-type emitter is ………… doped.
(a) lightly
(b) heavily
(c) moderately
(d) none of the above
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
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Power Semiconductor Devices » Exercise - 1 25. The device that exhibits negative resistance region is ........................ (a) diac (b) triac (c) transistor (d) UJT- Power Semiconductor Devices » Exercise - 1 9. The device that does not have the gate terminal is ............ (a) triac (b) FET (c) SCR (d) diac
- Power Semiconductor Devices » Exercise - 1 27. A diac is simply ........................ (a) a single junction device (b) a three junction device (c) a triac without gate terminal (d) none of the above
- Power Semiconductor Devices » Exercise - 1 16. When the emitter terminal of a UJT is open, the resistance between the base terminals is generally ............ (a) high (b) low (c) extremely low (d) none of the above
- Power Semiconductor Devices » Exercise - 1 28. After peak point, the UJT operates in the ........................ region. (a) cut-off (b) saturation (c) negative resistance (d) none of the above