This circuit was found in Siliconix documentation from the 1980s. Equivalent operational amplifiers can be used and the output current is very low.
This vox was found in Hughes documentation from 1968. The circuit uses components from the era. A...
This circuit is from Mullard documentation from 1969. Transistors support current equivalents. Output...
September 2017 - Microchip's MCP6411 operational amplifiers for frequencies up to 1 MHz are in...