This circuit is from an old American documentation from the 70s. Transistor 2N3904 can be replaced by BC548. The relay must have 100 mA of maximum current.
Found in the August 1994 issue of Electronics Now, this CMOS circuit uses the 4046, which is...
We found this circuit in an English publication from 1982. The power MOSFET can be of any type and the...
This tunnel diode oscillator was found in July 1986, Radio Electronics magazine. Note the low...