First of all, we’d like to give a big shout-out to [Afrotechmods]! After a long hiatus, he has returned to YouTube with an awesome new video all about op-amp characteristics, looking at the relatively ...

This circuit can be used to remotely monitor a loudspeaker, alarm, or audio source for presence of an audio waveform. It can also be directly connected across loudspeaker terminals used as a peak ...