This circuit was taken from a popular 90's Electronics. The LDR is mounted next to the LED to feed back the circuit.
Here we have an interesting circuit found in a 1981 publication that causes two LEDs to flash...
This circuit can flash for up to 30 months using alkaline batteries as shown in the table next to the...
This circuit, from a 2006 documentation, automatically controls the activation of a water pump, and...