This variable frequency oscillator for radio transmission covers the range from 1.6 MHz to 20 MHz, depending only on the coil used. The circuit is very stable and can be used in amateur equipment.
I found this circuit in an old Argentine publication from 1973. The components are no longer...
This circuit has an LED indication of the timing progress, having been found in an old...
This simple signal tracer was found in a Popular Electronics from the 90's. The transistor can be a...