This simple indicator circuit was found in a documentation from the 90s. Trimpots can have values between 2k and 10k, a series resistor is recommended to limit the current to the minimum setting.
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,...