This small source for low consumption projects was found in an old national documentation. The transistor is for general use and the transformer has 50 to 100 mA of secondary current.
This circuit was found in a Texas Instruments optoelectronics documentation. The gain depends on...
This oscillator circuit is from a Radio Electronics magazine from September 1960. The frequency depends...
Using a reed relay, this protection circuit depends only on the adjustment of the closing point by a wire...