This circuit uses a photo-SCR or LASCR that is not a common component today. The relay depends on the load, and the power is supplied by the power grid.
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...