Audio Cable Tester (CB3827E)

This simple circuit tests both monophonic and other two-wire audio cables. The circuit is powered by two common batteries.

OK 1783B Commercial Megaphone (CB18360E)
We found this circuit from a commercial megaphone in a Japanese publication in 1967. The circuit is...
Driver Amplifier For 50 ohm Line (CB19846E)
This circuit is from an old operating manual and can be implemented with operationals types that...
Sound Booster Stage (CB9881E)
This circuit was originally created to increase the power of car radios of the 790s and 80s that...