Question

The diode used in the circuit shown in the figure has a constant voltage drop at 0.5 V at all currents and a maximum power rating of 100 milli watts. What should be the value of the resistor R, connected in series with diode for obtaining maximum current?

(a) 6.76 Ω

(b) 20 Ω

(c) 5 Ω

(d) 5.6 Ω

Answer 1

The correct option is (c) 5 Ω.

Explanation:

Voltage drop across diode (VD) = 0.5 V; Maximum power rating of diode (P) = 100 mW

= 100 x 10-3 W

and source voltage (Vs) = 1.5 V.

The resistance of diode (RD)

And the value of the series resistor = Total resistance of the circuit - Resistance of diode

= 7.5 - 2.5

= 5 Ω