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 radio's transistor is powered with the signal's own energy, producing its amplification....
Found in a 90s Electronic Design, this circuit can be used as a shield in current projects. The...
The integrated circuit used in this regulator is not very common today. The circuit is from old...