This biestable vox circuit was found in an old documentation. The circuit makes use of components of the time (80's) and can work as a shield since the power is 5 V.
This noise generator uses the thermal noise of a common diode junction. The circuit is from an...
This circuit can monitor the charge and discharge of batteries. The circuit is from a Linear...
This simple electroscope with bipolar transistors is not the most sensitive, but can detect static...