This circuit was found in a 1967 US documentation. It shows how to build a gain control by digital signals. The circuit can be used as a shield. FET can be a modern equivalent.
This circuit was found in an old TTL circuit manual. The circuit must be powered by 5V, and the...
This amplifier for biological research was found in an Electronic Design from 1964. The...
Found in National Semiconductor publication from the 1980s. This gain-100 circuit can be...