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.
When the sensor X1 is opened, the relay is energized. When waiting, the current drained is very...
Based on the LF256 operational amplifier, this circuit was found in the September 1989 issue of...
This circuit was found in a 1968’s Motorola documentation. The transistor is from that time. The...