Of the diodes shown in the following diagrams, which one is reverse biased?
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- [figure]
- [figure]
- [figure]
Answer
(3) [figure]
Solution
The triangle of the diode symbol is the p-side (anode) and the bar is the n-side (cathode). Reverse bias needs Vp < Vn.
(1) Vp = -5 V (through R), Vn = -12 V Vp > Vn, forward biased
(2) Vp = 0 V (earth), Vn = -10 V forward biased
(3) Vp = 0 V (earth), Vn = +5 V Vp < Vn, reverse biased
(4) Vp = +10 V (through R), Vn = +5 V forward biased
Answer: (3)