Signal generator (CB21057E)

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

Touch Switch (CB10567E)
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
12 W Amplifier (CB13679E)
The integrated circuit of this amplifier is not very common today. The output transistors can be...
2400 Hz Neon Oscillator (CB21457E)
Found in an old documentation about neon lamps, this circuit has the frequency basically...