We found this circuit in an old Mullard (Philips) documentation on the 555 and 556 integrated circuit (double 555). The relay must be 12 V with contacts that support the horn current.
This circuit was obtained in a 1990 English magazine. The circuit can be assembled with equivalent power...
Varactor diodes are our varicaps of today. This circuit for switching signals in an RF circuit was found...
This basic circuit was found in RCA / GE documentation from the 90s. In it we have the way to...