This circuit was found in December 1983 Radio Electronics magazine. The maximum output current is 1 A and the supply voltage ranges from 4 to 28 V.
Today we have more compact solutions. This is from a Radio Electronics magazine from October 1990....
This filter was found in Texas Instruments documentation from the 1980s. The circuit uses a common...
16 commercial test circuit for tubes and transistors appeared in Radio Electronics magazine in...