This low-noise, low-drift amplifier was found in a 90's EDN. It can be implemented with modern equivalent operational amplifiers. The font must be symmetrical.
In the figure we have the simple way to obtain a digital inverter using a general-purpose...
This circuit works with only 1.5 V and can be powered by a solar panel. The circuit is from 1991....
This circuit was found in a 1969 EEE. The circuit uses transistors from the era that can be...