Found in an old Popular Electronics this circuit appears in other variations on this site and in this section. It uses a 7-segment common anode LED display as an indicator.
Using the 4001 integrated circuit, this latching relay can employ any general-purpose transistor. The...
Suggested by a 90s Electronic Design, this circuit drains only 0.25 mA from its source. Listening...
The frequency of this oscillator depends on the amount of light incident on the LDR. The circuit,...