Rectification In Physics-Half Wave Rectification and Full Wave Rectification

The process of converting the A.C waveform into the D.C waveform is called rectification. Rectification is the process of turning an alternating electric current waveform into a direct current waveform.

 The device used for rectification is called a rectifier. Two PN junction Semiconductor diodes are extensively used for this purpose.

Download the pdf notes of Rectification-Half Wave Rectification and Full Wave Rectification Class 12 Physics

Methods of Rectification

There are very common methods of rectification.

• Half-wave rectification

• Full-wave rectification

Half Wave Rectification

A type of rectification in which only one-half cycle of the input AC current is converted into D.C. current is called Half-Wave rectification.

A diode is connected in series with a load resistor and they are connected to an alternating voltage source of period T.

Working of half wave rectifier

During the positive half cycle of the input 0 to T/2 the diode D is forward biased and offers very low resistance to current and it flows through the resistor R.

 This current causes a potential drop across the resistor R in accordance with the alternating input.

During the negative half cycle T/2 to T the diode is reverse biased and it offers very high resistance and no current flows through R and the potential difference across it is almost zero.

 This process is repeated for every cycle. The output voltage is not smooth but appears in pulses and is called pulsating D.C

Full Wave Rectification

That rectifier in which both the input cycles appear as the output DC is called full wave rectification.

 It contains four diodes D₁,D₂,D₃, and D₄ connected to form a bridge.

The A.C. supply to be rectified is applied diagonally to the opposite ends of the bridge through the transformer or directly. Between the other two ends of the bridge, the load resistor R_L is connected.

Working of Full Wave Rectifier

During the positive half cycle of the input voltage, the end P becomes positive and Q becomes negative.

 This makes diodes D₁ and D₃ forward biased while diodes D₂ and D₄ are reverse biased.

Therefore only diodes D₁ and D₃ conduct. It can be seen that the current flows from A to B through. During the negative half cycle, the end P becomes negative and the end Q becomes Positive. This makes the diodes D₂ and D₄ forward biased and D₁ and D₃ reverse biased.

Therefore only D₂ and D₄ conduct. Now again the current flows from A to B through the load resistor in the same direction.

Therefore D.C output is obtained across the load. The output Voltage is not smooth but pulsating. It becomes smooth by using a circuit called (Combination of capacitors and inductors in the circuit as a filter).

Frequently Asked Question-FAQs