The frequency of this circuit can be varied from zero. The circuit uses the CMOS 4046 and was found in the November 1984 issue of Radio Electronics magazine. The base frequency is given by C1.
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...