This Hughes circuit is from 1968. Equivalent modern components can be used. The input impedance is 1000 M ohm.
This 80's circuit has an input resistance of the order of 880 M and gain 10, using operational...
We found this circuit in the Audio Handbook of the National Semiconductor of 1977. The circuit is used...
Published in 1988 in Hands-On Electronics, this circuit converts the 12 V of a battery into 120 V...