This fast Schmitt trigger operates at frequencies from 10 Hz to 100 Hz, with very short rise time. The circuit is from an American documentation from 1968.
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...