The I–V characteristics of an electronic device are shown in the figure. The device is : [figure]
- a solar cell
- a transistor which can be used as an amplifier
- a diode which can be used as a rectifier
- a zener diode which can be used as a voltage regulator
Answer
(4) a zener diode which can be used as a voltage regulator
Solution
The curve passes through the origin, conducts in forward bias, and in reverse bias carries only a tiny current until a sharp breakdown, after which the current rises steeply while the voltage stays nearly constant.
(1): a solar cell's curve lies in the fourth quadrant and does not pass through the origin, so (1) is wrong.
(2): a transistor has output characteristics for different base currents, not one two-terminal curve, so (2) is wrong.
(3): a rectifier diode is not operated in the breakdown region, so (3) is not the best description.
(4): sharp reverse breakdown at constant voltage is the working region of a zener diode, which is used as a voltage regulator, so (4) is correct.
Answer: (4)