Jawaharlal Nehru Technological University Hyderabad B.Tech III BASIC ELECTRONICS Previous Question Paper (September - 2021 - R13)

A semiconductor diode is represented by a triangle pointing towards a vertical bar. The triangle represents the anode (positive terminal) and the bar represents the cathode (negative terminal).

For forward bias, the anode is connected to the positive terminal of the voltage source and the cathode is connected to the negative terminal. The conventional current flows from the anode to the cathode, in the direction of the triangle's arrow.

A half-wave rectifier converts AC voltage into pulsating DC by allowing only one half-cycle of the input waveform to pass through the load.

1. During the positive half-cycle of the input AC signal, the diode is forward-biased and acts as a closed switch, allowing current to flow through the load resistor. The output voltage across the load follows the input voltage.
2. During the negative half-cycle, the diode is reverse-biased and acts as an open switch, blocking the current. Consequently, the output voltage across the load remains zero.
3. This process repeats, resulting in a unidirectional but pulsating output voltage consisting only of positive half-cycles separated by gaps.

The efficiency of a half-wave rectifier is low, and the output contains significant ripple, which is why it is typically used in low-power applications.