Found in old documentation, this circuit has only the most difficult component to obtain the PUT. The sensors are electrodes placed in the reservoir. The circuit directly controls an AC power load.
The frequency of this Pierce oscillator, found in 1969 documentation, depends on the crystal. The...
We found this Nicad cell charging circuit in an English publication from the 1970s. The circuit can...
In the figure we have a constant current source for Shape Memory Alloy in wires or Alloy with...