This 3-step circuit for generating digital signals was found in the November 1976 issue of Radio Electronics magazine. The maximum frequency depends on the flip flops.
This power control with SCR was found in Radio Electronics from April 1966. The components are...
We found this circuit in a documentation for radio amateurs from 1977. The circuit can be changed to...
We found this RF amplifier in documentation from the 1970s. Field effect transistors support...