Bmet Cdc Set A Vol 3 Study Guide Rated A+

29. (408) The creation of a magnetic field with current is a. paramagnetism. b. ferromagnetism. c. electromagnetism. d. natural magnetism. {Ans: c. electromagnetism}20. (405) Which type of circuit is used when it is necessary to have different voltage and current values from a single supply voltage? a. Series. b. Parallel. c. Series-parallel. d. Direct current (DC). {Ans: c. Series-parallel.}57.(416) Which device has two base leads? a.Positive-type and negative-type material (PN) junction diode. b."Pointing-in" PNP-type bipolar transistor. c.Unijunction transistor. d.Zener diode. {Ans: c.Unijunction transistor.}58.(417) Which semiconductor device requires an external trigger pulse (instead of an input signal) for operation? a."Not pointing in" positive-type and negative-type material (NPN) transistor. b.Silicon controlled rectifier (SCR) .c.Unijunction transistor (UJT). d.Zener diode. {Ans: b.Silicon controlled rectifier (SCR)}21. (405) What is the minimum number of resistors required to form a series parallel circuit? a. One. b. Two. c. Three. d. Four. {Ans: c. Three.}26. (407) What is the frequency in hertz (Hz) of an alternating current (AC) sine wave that repeats itself 500 times in 1/5 of a second? a. 25 Hz. b. 100 Hz. c. 250 Hz. d. 2,500 Hz. {Ans: d. 2,500 Hz.}