Using components of the time, this 3 and half digit scale was found in an Electronics Now from the 90s. The circuit is powered by a 9 V battery.
In the figure we show our first circuit that consists of a simple touch switch capable of driving a...
This circuit was found in an 80's Electronic Engineering. The power supply must be symmetrical. The...
This metal detector was found in a French magazine Radio Plans from 1977. The phone can be a...