In the figure we have the way to use a zener instead of a filter capacitor. The zener can have the same effect as a 1,000 uF capacitor with 300 mA in the indicated circuit.

In the figure we have the way to use a zener instead of a filter capacitor. The zener can have the same effect as a 1,000 uF capacitor with 300 mA in the indicated circuit.