Using a MAX644 this circuit was found in the April 1989 issue of Radio Electronics magazine. The circuit is for a 5 V voltage and 50 mA current output.
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...