This simple circuit makes use of neon lamps to indicate the voltage of a power grid. The lamps are common neon and the circuit indicates whether the voltage is 110 V or 220 V.
This circuit is from a 1987 magazine, but it can still be easily assembled, as the components are...
In the figure we have a second order filter with very high input impedance, using an operational...
This circuit is from Motorola's Linear Interface ICs from 1993. The MC1723 is the equivalent of...