Found in a 1967 Electronics World, this preamplifier uses an integrated circuit from that time, difficult to obtain today. The maximum frequency is 15 kHz.
This circuit, published in the 1980s, can be applied to operational amplifiers of almost any type....
This configuration can be found in several articles on this site. The one shown in the diagram is from...
This circuit that drives the load when the logic output is at the low level, was obtained in a...