This third-order Butterworth filter was found in American documentation from the 1980s. Formulas for component calculations are attached to the diagram.
This commercial transistor radio was manufactured in Japan in the 1960s. The circuit has only 3...
This useful signal injector using two transistor was found in a Radio Electronics Magazine from...
In the figure we have the way to control a flip-flop with the 4069 from positive pulses. The...