Calculation of Capacitance after Full-Wave Rectification

After full-wave rectification, the signal requires a large capacitor to reduce ripple. How should the value of this capacitor be calculated?

In the calculation of capacitors in capacitor filter circuits, this concept was introduced in college textbooks from the 1960s. In recent years, the use of approximate formulas has generally been sufficient to meet engineering requirements. An approximate formula for capacitor calculation during full-wave rectification is: C >= (1.5-2.5)T/RL.

In the formula: T represents the AC cycle of the power source, RL is the load resistance.

The above calculation does not consider the voltage regulation stage. Since the voltage regulation circuit itself has a suppressive effect on AC ripple, the filter capacitor can be appropriately reduced when the voltage regulation stage is adopted.