Bike speedometer (CB20497E)

This circuit can be powered by a solar cell. The circuit is from a 1991 documentation having a phototransistor as sensor.

741 Semilog Amplifier (CB25831E)
This circuit with the 741 operational amplifier was found in the March 1995 issue of Electronics Now...
Divider by 10 (CB6898E)
This circuit was found in a General Electric documentation from 1966. It uses discrete components...
Operational Pulse Generator 1 (CB14830E)
We found this circuit in a French technical documentation from 1982. The circuit can be...