Found in a 1990s American documentation, this circuit provides an output voltage approximately 4 times that of the input voltage. Diodes are general-purpose types.
This circuit turns on a lamp after the time set on the potentiometer. The circuit is from a Radio...
This signal amplifier for ATV in the 427 to 439 MHz band was found in a magazine 73 for radio...
This amplifier has a few Watt output, using old transistors. The speaker is 45 ohms, but with...