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 uses a digital module from the time. We found it in February 1984 Radio Electronics...
This low current solenoid driver was found in an ancient American documentation. The solenoid must be...
A safe way to obtain a sinusoidal signal of excellent quality and low frequency without the need...