Question

A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output?

• A. Load resistance
• B. A centre-tapped tranformer
• C. p-n juntion diodes
• D. Capacitor

Answer 1

The Correct Option is D

Step 1: Understanding the Full-Wave Rectifier Circuit:

A full-wave rectifier is a circuit that converts both positive and negative halves of an AC signal into a unidirectional (DC) signal. It uses two diodes and a center-tapped transformer to rectify the signal. However, the output of a full-wave rectifier still contains ripples (AC components) that need to be removed to smooth the DC output.

Step 2: Components of a Full-Wave Rectifier:

• p-n junction diodes: These are responsible for rectifying the AC signal by allowing current to flow only in one direction.
• Center-tapped transformer: This step-down transformer is used to provide the necessary AC voltage to the diodes, and the center tap provides a reference point for the rectification process.
• Load resistance: This is the resistance through which the rectified current flows to the load. It does not play a role in removing the ripple.
• Capacitor: A capacitor is used to smooth out the ripples in the rectified output. It does this by charging during the peaks of the waveform and discharging during the troughs, thus filling in the gaps and reducing fluctuations in the DC output.

Step 3: Analyzing the Given Options:

Option 1: Load resistance

Load resistance does not remove the AC ripple. It simply provides a path for the rectified current to flow to the load. It is essential for completing the circuit, but it does not filter out the ripple.

Option 2: A center-tapped transformer

The center-tapped transformer provides the necessary voltage for the rectifier, but it does not perform any filtering. Its role is crucial in the rectification process, but it does not remove AC ripple.

Option 3: p-n junction diodes

The diodes rectify the AC signal by allowing current to flow only during one half of the waveform. However, they do not filter out the AC ripple. Their job is to convert the AC signal into a pulsating DC signal.

Option 4: Capacitor

The capacitor is the component that removes the AC ripple from the rectified output. It smooths the rectified signal by charging during the peaks of the AC waveform and discharging during the troughs, thereby filling in the gaps and creating a more stable DC output.

Step 4: Conclusion:

The component that removes the AC ripple from the rectified output is the capacitor, as it smooths the pulsating DC signal and reduces the ripple.

Answer: The correct answer is Option 4: Capacitor.