This circuit was obtained in a 1978 publication. The supply can be symmetrical from other voltages. Frequency can be changed by changing the capacitors.
This circuit incorporates the passive control of the previous circuit and was also found in the...
This configuration is suggested by Mullard (Philips) in an old manual of 555 integrated circuits....
This interesting circuit triggers the alarm when sunlight hits the sensor. The circuit can be used to...