Can I use a Schottky diode instead of a common diode in a power supply? What improvements do I have in the circuit?
It all depends on where the circuit is going to be used, you can have improvements or not. As long as the diode has the same current capacity and the same voltage as the diode to be replaced, nothing prevents its use. If the circuit works with audio signals, we can have an improvement due to the lower conduction voltage.