We found this circuit in a Poptronics from 1998. The circuit can be extended to more competitors with another 4011. The power can be made with voltages from 6 to 12 V.
The sensors of this liquid alarm are formed by two pieces of wire with the ends peeled off. The...
This circuit was found in an old neon lamp applications publication. The relay must be in...
We found this circuit in the December 1968 issue of Radio Electronics magazine. The circuit is...