This circuit was found in a 1966 EEE. What it does is it converts the logic levels of 0 V and +4 V into -6 V and +6 V. Some older type transistors can be replaced by modern equivalents.
This filter can be implemented with almost any operational. The power suppply must be symmetrical. ...
This traditional circuit of old documentation uses a 0-1 mA milliammeter and has several scales....
This simple 2-transistor radio is from Radio Electronics in October 1952. The circuit outputs a...