Found in a 1988s Radio Electronics, this circuit uses transistors of general use to increase the intensity of signals up to about 30 MHz. The power can be done by battery because the consumption is low.
This simple electroscope with bipolar transistors is not the most sensitive, but can detect static...
This oscillator for various frequencies was obtained from a 1980s telecom documentation. The...
This circuit is from a July 1970 Radio Electronics magazine. The sensors are metal probes. The 18 V...