This high impedance circuit was found in 1967 documentation by Ferranti. The original operational amplifier is from that time. The circuit can be implemented with modern equivalents.
This circuit works both as a preamplifier and activates a relay when speaking in front of the...
This simple CMOS touch switch with bistable action must not be powered by a source without a...
This circuit activates an incandescent lamp (it cannot be of another type) when it gets dark. The...