Mini Organ (CB21653E)

This toy organ was found in Popular Electronics from January 1967. It can be constructed from modern equivalent transistors.

DC motor control (CB22298E)
This circuit was obtained from an American publication from the 60's. The transistors are...
Differential Light Sensor (CB11589E)
This circuit detects light variations using two LDRs as sensors. Operational amplifiers and...
Audible Indicator for Car (CB26291E)
Using the 555 this circuit was found in a Popular Electronics from the 90's. The circuit directly...