This circuit was obtained from a 1980's QST magazine. The circuit can generate 1 to 15 MHz signals with 1 Vpp at 50 ohms load. Used transistors are still common today.
This simple circuit triggers when light strikes the sensor. The relay is of the sensitive type with a...
We found this 555 integrated-circuit tester in an old Electronics Hobbyst from 1977. The circuit is...
The shield circuit shown in the figure has elements to obtain the maximum gain with the maximum...