Found in a 1965 General Electric circuit manual, this circuit uses SCRs from that time. Modern equivalents according to the power can be used.
This circuit activates a relay when the water reaches the sensors. The circuit is from a magazine...
The noise comes from the PN junction of a common silicon diode. Since no gain is given by the...
We have here an interesting audio preamplifier, which can be useful to those who are looking to...