This longwave signal booster circuit was found in the 1995 Encyclopedia of Electronic Circuits Volume 5. Note the dimensions of the board. The transistor is a general-purpose transistor.
This simple SCR trigger was found in a 1965 General Electric SCR manual. The circuit makes use of a...
Using an old integrated circuit, this low power amplifier, on the order of a few watts, includes tone...
This circuit with only one transistor was found in Japanese documentation from the 1960s. The...