This low frequency sinusoidal oscillator was obtained in documentation from the 1970s. Operational equivalents can be used. The FET is a general-purpose type.
This circuit, with a 12 V input, was found in a Popular Electronics from the 1990s. Information is given...
This circuit is the equivalent of the CB121, but is triggered with the negative transition of the...
We found this circuit of a clamp-type ammeter in a Japanese documentation from the 1960s. The...