This excellent tube preamplifier was found in Radio Electronics magazine from July 1958. The power supply was not included. The circuit has several inputs.
With this circuit, from an old operational datasheet, it is possible to measure the CMRR,...
Found in a Popular Electronics from the 90s, this circuit can be adapted to use LEDs. The power...
The circuits shown in the figure, that of an infrared video signal transmitter and receiver, were...