Found in an Electronics Now from the 90s, this circuit uses components that are still common. The LM3900 is a transconductance operational amplifier.
This circuit, from an 80's publication, detects the SCA (Announcer Eliminator) signal from FM...
The circuit is from the Linear Application Handbook. The resistors determine the voltage applied to...
USB58xx and USB59xx Devices Integrate a 2:1 Multiplexer to Support Reversible Connection of USB...