This circuit was taken from Maxim documentation from the 1990s. It can be implemented on the basis of modern operational amplifiers. Power supply doesn't have to be symmetrical.
We found this circuit in a publication on operational amplifiers from 1978. The circuit is made...
This circuit allows the detection of RF signals using the lowest range of direct currents of a...
This circuit was found in the Radio Electronics magazine of May 1990. The supply voltage depends on...