This circuit generates various types of sounds and can be used as a toy. The circuit is from Radio Electronics from January 1983. The amplifier can be replaced with a more modern type.
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....