Two-tone solar buzzer (CB20493E)

This circuit was found in a 1991 publication. The transistor can be a general-purpose type.

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...