The sensors of this liquid alarm are formed by two pieces of wire with the ends peeled off. The relay depends on the supply voltage that can be between 3 and 12 V. The transistors can also be the BC548.
This dimmer was found in the Electronics Experimenter Special projects of 1983. The circuit uses...
The circuit shown is from the 1977 GE semiconductor manual. More modern equivalent SCRs can be...
What characterizes this type of configuration, which we find in a Texas Instruments application manual,...