Suggested by General Electric in a 1965 publication this circuit uses a light bulb. Can be changed to use LED and capacitor can be 22 uF.
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...