Found ina 1970 American documentation this fast-reading circuit uses a photodiode. Transistors support modern equivalents. The circuit can be used as a shield.
Found in a 1980s American documentation, this circuit appears with variations elsewhere in this...
The circuit shown, with the printed circuit board, was found in an article in the June 1990 issue...
This interesting circuit converts BCD signals into a voltage that can be used in an analog...