Signal generator (CB21057E)

Found in Popular Electronics, this '90s circuit generates harmonic-rich signals for testing audio equipment.

Composite amplifier (CB20632E)
This circuit combines a low-offset and a high-speed operational amplifier. The circuit was found in...
Touch Switch (CB26207E)
We found this circuit in the 1983 Radio Electronics Special projects magazine. The components are...
Modulated Oscillator (CB22067E)
This power oscillator uses an LM380 amplifier. We found it in old English documentation. The C3...