Using the 723 integrated circuit, this power supply has the voltage determined by R2 and R3, which can be changed. The circuit is from a Radio Electronics magazine from July 1971.
This Schmitt trigger in current mode for frequencies up to 50 MHz was found in a 1969 Motorola manual....
VR can be from 50 to 220k it is recommended to connect a 100-ohm resistor in series. The lamp may...
This circuit was published in a 1977 English magazine, but remains current, since we can assemble it...