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 was found in 80's Popular Electronics. Transistors are commonly used. The...
This low current source uses some components that are hard to find in ours. The transformer is a...
This circuit is from a manual based on information from Japanese components from 1981. The power...