Found in a Motorola documentation from the 70s, this circuit makes use of transistors of the time. Modern equivalents can be used. The diode also supports an equivalent.
Found in American 90’s documentation, this circuit generates 300 Hz depending on the capacitors...
According to what is said, the bugs are the female insects (mosquitoes, muriçocas and others)....
Found in a 90s nHands On Electronics, this circuit triggers a relay that shuts off the load when...