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.
This circuit is from a 1968 publication. Here we have several types of resistive sensors with...
This circuit is from a 1965 Electronic Design. The transistors may be general purpose and the...
This is the basic configuration of a voltage comparator with the Norton LM3900 amplifier. The...