Found in a 1970 documentation, this circuit makes use of 741 operational amplifiers that are common today. Note that the power supply must be symmetrical.
This circuit produces a loud sound in the speaker when water level reaches the sensor. The power...
May 2016 - It can be obtained from Mouser Electronics new display 1092 from VDC. The new LED...
This Motorola circuit is from 1965. Collector currents must be 7 and 12 A for transistors....