The figure shows how to use CMOS inverters as amplifiers. The circuit is from a Radio Electronics from April 1984. The supply voltage can be between 3 and 12 V.
Found in a 90s Popular Electronics, this circuit uses two PLL tone recognizers to trigger by touch an...
This Hughes circuit is from 1968. Equivalent modern components can be used. The input impedance is...
This circuit is from 1995 documentation. In the original, the source is symmetrical at 12 V, but...