Introduction:

In electrical circuits, a C filter is used to reduce the ripple voltage in a power supply. It consists of a capacitor connected in parallel with a load resistor. The capacitor acts as a filter and smoothens the output voltage by storing electrical energy during the high voltage peaks and releasing it during the low voltage periods.

Effects of increasing the load resistance (R):

When the load resistance (R) is increased in a C filter, the following effects can be observed:

1. Ripple voltage reduction: Increasing the load resistance (R) in a C filter reduces the ripple voltage. Ripple voltage is the AC component present in the output of a rectifier circuit. With a higher load resistance, the capacitor has more time to charge and discharge, resulting in a smoother output voltage. This leads to a reduction in the ripple voltage.

2. Ripple factor reduction: The ripple factor is a measure of the effectiveness of a filter in reducing ripple voltage. It is defined as the ratio of the RMS value of the AC component to the DC component of the output voltage. By increasing the load resistance (R), the time constant of the RC circuit is increased. This results in a higher charging time for the capacitor, thereby reducing the ripple factor.

3. Improved voltage regulation: Increasing the load resistance (R) in a C filter improves the voltage regulation. Voltage regulation refers to the ability of a power supply to maintain a constant output voltage even with changes in the load. With a higher load resistance, the voltage drop across the load resistor decreases, leading to improved voltage regulation.

4. Stability: Increasing the load resistance (R) can improve the stability of the C filter. The stability of a filter refers to its ability to maintain a constant output voltage despite variations in the input voltage or load. With a higher load resistance, the C filter becomes less sensitive to changes in the load, resulting in improved stability.

Conclusion:

In conclusion, when the load resistance (R) is increased in a C filter, the ripple voltage is reduced, the ripple factor is decreased, voltage regulation is improved, and the stability of the filter is enhanced. Therefore, the correct answer is option 'A' - the ripple factor is reduced.