Found in Motorola documentation from the 90's, this circuit has a high input impedance. The power supply must be symmetrical. The circuit can be implemented with modern operational amplifiers.
The setting of this power supply is only 0.1%. We found it in a 1969 US documentation. Transistors...
We found this interesting transistor generator in European documentation from the 1980s. The...
The circuit shown in the figure uses two of the four operational amplifiers found on the LM324...