This circuit of the 70's uses transistors of the time. The circuit can amplify signals from 10 Hz to 100 kHz and modern equivalent components can be used. The circuit is from Ferranti.
November 2016 - The new Ohmite TO-126 power resistors in the range of 0.09 Ω to 51 kΩ with...
Other CMOS gates can be used in this sensor, which we found in the July 1995 Electronic Now...
We found this circuit in a 1965 Electronic Design. Transistors are still common but admit...