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 circuit is placed between the instrument pickup and the amplifier input. The same version can...
This circuit triggers on a lamp when the sensor (a metal plate us touched). Up to 100 W...
We obtained this circuit from a 1993 documentation. The circuit has current and voltage ranges that...