Found ina 1970 American documentation this fast-reading circuit uses a photodiode. Transistors support modern equivalents. The circuit can be used as a shield.
We found this interesting timer circuit or CMOS timer in a 1988 publication. The circuit is still...
This circuit found in Radio Electronics can be used in games to produce a random pulse train. The...
We found this amplifier with high input impedance and low capacitance, using FET, in a...