This ultra-low noise amplifier and simple power supply was found in Analog Devices documentation from the 90's. The circuit can be implemented with modern equivalent components.
In this circuit, from a 1977 publication, we have the traditional version of a filter that rejects 1...
The integrated circuit used in this application is uncommon today. However, the basic...
This physical line servo control uses components that are not currently common. The circuit is from...