Using the 555 and 4020, this timer was found in the July 1994 Radio Electronics magazine. The relay is voltage-dependent, and the transistor is general purpose.
This 1992 circuit operates in the range of cordless phones used at the time. The circuit is based...
This different circuit uses a relay as an oscillator, whose frequency is determined by C1, and to...
This antenna or booster amplifier operates with signals from the midband (MW) range up to the VHF...