This circuit using only transistors was obtained from Ferranti's 1969 documentation. It can be made from modern transistors. The circuit is 4 bits.
This sensitive motion sensor with inductive sensor was found in a 90s Elektor. The circuit uses only...
This simple balance indicator for sound equipment was found in a 1982 documentation. The M1...
This circuit was found in a 1992 documentation. It uses a photo diode as a receiver and an...