This circuit is from Radio Electronics from March 1985. The circuit uses common components at the time and LEDs as indicators. The power supply is 9V.
This circuit is from an old documentation of Radio Shack from the 70s. The transistor should...
When the power is cut off, this circuit keeps the flashlight on for a while, allowing it to be...
This circuit was obtained in an old Popular Electronics. It makes use of quite common components....