Based on a unijunction transistor, this circuit was found in the January 1994 issue of Electronics Now magazine. The frequency range depends on C1, which can be changed.
This circuit automatically inverts the test leads connection according to the polarity of the...
This circuit was found in a publication from the 90s. The circuit can be assembled with modern...
This filter, from an audio publication from 1977, passes the frequency range corresponding to the...