For the circuit shown in the figure identify the correct output option if diodes are assumed to be ideal :

Concept:

Zener Breakdown

• A zener diode is a heavily doped semiconductor device that is designed to operate in the reverse direction.
• Under the forward-biased condition, the zener diode work as a normal PN junction diode.
• During the reverse-biased condition, when the voltage across the terminals of a zener diode reaches the zener Voltage (breakdown voltage), the junction breaks down, and the current flow from the cathode to the anode.
• Under breakdown conditions, the voltage across the zener diode becomes constant and is independent of the current. Under such conditions, the value of voltage across the zener diode becomes equal to its breakdown voltage.

Case 1: During +ve half

From \(0<V_{in}<5\)

D1 is forward biased

D₂ and ZD are reverse-biased

D₁ ON, D₂ OFF, and ZD OFF

V_o = V_in

From \(5<V_{in}<20\)

D1 is forward-biased but ZD conducts as it is in the breakdown region.

D2 is reverse biased

D1 ON, D2 OFF, and ZD ON

Vo = 5V

Case 2: During -ve half

D₁ is reverse-biased

D₂ and ZD is forward biased

D1 OFF, D2 ON, and ZD ON

Vo = 0 V

Therefore, the output waveform is given below: