This alarm circuit was found in April 1975 Radio Electronics magazine. The circuit uses a 12 V power supply and relay but can be modified to work with other voltages.
An oscillator that uses two gates is not suitable for critical applications, as it tends to pick...
We found this circuit in a 1991 Hobbyst Electronics. The circuit makes use of an unusual...
We found this circuit in a 1982 documentation. An intercom to be good must be sensitive and have...