This receiver uses old transistors that are equivalent to BC548 and BC558. The photo diode is of any type. The receiver can be used on a highly sensitive audio link.
This circuit goes into operation producing a sound on a small speaker when the supply voltage...
In the figure we have two simple configurations of voltage doublers. Resistors and diodes are...
This timer was found in an English publication from 1979. The circuit can be powered with voltages...