Voltage Double Circuit with timer IC 555

This is a voltage double circuit which build using well-known timer IC 555. The circuit is very simple, and is easily to build. Construction is not crucial.

Here the schematic diagram:

Rectifier diodes should be ultrafast (UF4004 or similar), or you can use 1N4148 signal diodes. Losses will be slightly higher if you use signal diodes, or lower if you wanted to go to the trouble of using Schottky diodes - the latter are not warranted in such a simple circuit (IMO). The zener diode is to protect the circuit against transient overvoltage, and is optional.

Voltage Double Circuit with timer IC 555
source: http://sound.westhost.com/project95.htm

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