This simple tester was found in a Popular Electronics from the 90s. The circuit is powered by two 9 V batteries since it requires a symmetrical source.
We found this circuit with unijunction transistor in an old publication from the 80's. The circuit...
This simple emitter can be used in animal conditioning, to scare animals and even in biology...
Found in an older Radio Craft, this circuit covers the aerial band from 118 to 136 MHz. No...