This circuit indicates a digital value through a moving bar. The circuit is TTL and must be powered by 5 V. We find this circuit in a Texas Instruments optoelectronics manual.
This small signal injector generator was found in the February 1971 issue of Radio Electronics magazine....
This circuit that generates signals between 1.5 and 2 kHz was found in a documentation from the...
Other operational Amplifiers in the series, such as the MC34072, MC34074, MC35071, MC35072,...