Found in a Popular Electronics from the 90s, it applies to the old answering machines that used tapes. It emits a warning beep on the drive.
We found this circuit in a 1967 Electronics World. It analyzes a transistor by determining its...
This circuit monitors the output level of an amplifier. The circuit is set to R4 and can be...
Originally designed for an incandescent lamp, this flasher or pulser can be adapted to operate with...