This circuit was found in the August 1996 Electronics Now magazine. The circuit is based on an operational circuit whose type determines the gains and limits for the frequency.
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...