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.
For the 600 kHz range coil is formed by 35 turns of 28 AWG wire on a ferrite core with a diameter...
Found in a 1970’s documentation, this circuit uses components of the time, uncommon today. |...
This 2003 circuit uses two types of sensors: by reed-switch and by infrared. If the magnetic...