Question

An a.c voltage of peak value 10 V is connected in series with a silicon diode a load resistance of 100 Ω . The forward resistance of the diode to 20 Ω . The peak output voltage across the load resistance will be

(1) 5 V

(2) 7.75 V

(3) 9.3 V

(4) 10 V

Answer 1

(2) 7.75 V

Barrier potential of silicon diode = 0.7 V

Peak current through the diode in the circuit = 10-0.7/100+20

= 77.5 mA

Peak output voltage = 77.5 mA x 100 Ω 

= 7.75 V