Semiconductor Electronics

For the given circuit of p-n junction diode, which is correct? [figure]

1. in forward bias the voltage across R is V
2. in reverse bias the voltage across R is V
3. in forward bias the voltage across R is 2V
4. in reverse bias the voltage across R is 2V.

Answer

(1) in forward bias the voltage across R is V

Solution

R and the diode are in series across the supply V.

∵ In forward bias an ideal diode has (nearly) zero resistance ⇒ no voltage drop across the diode.

⇒ Voltage across R = V

∵ In reverse bias the diode does not conduct ⇒ current = 0 ⇒ voltage across R = 0

∴ In forward bias the voltage across R is V.

Answer: (1)