This circuit was found in a 90s Electronic Design. The circuit directly controls a triac that is loaded with a heating element. The triac depends on the power on the load.
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...