62. Op Amps as Comparators

ERROR - I made a mistake in the drawing seen at the 10:30 time. The 10K resistor and 3K resistor should be reversed. The calculations are correct - had a brain dump ;)
A discussion of various comparator configurations and the use of hysteresis. It it through the use of hysteresis that we get the extremely useful Schmitt trigger. As always, we talk theory and do experiments to prove the former.

[@electrifyingelectron9792]

This is super awesome. Cleared my confusions about comparators. Thanks

[@Darkipod]

This is an incredible and very comprehensive video, thank you so much for this.

[@TheOffsetVolt]

You are welcome and thank you. Sometimes I think they get a little too involved. People seem to prefer something on the order of a 10 minute session - tough to do in technical fields.

[@Darkipod]

I completely agree, this video does a great job at summing up what my electronics 2 class made terribly difficult for no reason.

[@mekuranda]

Bugger...only just found your channel....great presentation ...made follow along with your logic and reminded me of long past theory ....if you still read comments..i.e. for giggle value...in your last comp cct ..when would the output ever be 0V?

[@srinivasan7901]

Your teaching is excellent sir. Hands off to you sir

[@TheOffsetVolt]

Thanks a ton

[@arsalanrashid4555]

Sir at 12:09 I think the Inverting Input Voltage should be (10/13)*15 V

[@worldoflard]

I believe the resistor values were the wrong in the circuit diagram. On the breadboard they were the other way around.

[@fantozzi30]

Hi. As far as I can see, when you are testing the Schmidt trigger circuit, (starting at 33:15) the 2kohm load resistor connected btw. the output and GND is present as well. This load resistor (with a much lower resistance than R1 or R2) is therefore in paralel with R1 and R2. Isn't this going to affect the value of the threshold levels?

[@alibehrouz9833]

you are a kind man thanks a ton fot making these great videos

[@TheOffsetVolt]

Thank you although some may disagree :) I appreciate the feedback though and thank you for watching.

[@electronicssciencebysherry5050]

As hobby I appreciate your video

[@Iosens]

Hmm, why are you starting with 0V at the output at 41:06? Should the comparator not always be at (close to) +/- supply?

[@TheOffsetVolt]

It's necessary for calculation of the trip points. Because of the zero volt output, it essentially is a ground with respect to R3 to set one trip point, R3||R2. This changes to another equation when the output goes high to select the upper trip point, R1||R2.

[@leenkaur9528]

really good can not thank u enough

[@-VHSorPlanetTelex]

Excelent video.

[@TheOffsetVolt]

Very much appreciated and thanks for your time.

[@viktor2160]

30:56, there are some error. 100*50 nA=50 uA. it should be 5 uA.

[@TheOffsetVolt]

Yes it should - there is always a misstatement that I don't catch in editing.

[@vant4888]

Are you talking about using opamps as comparators? Actual comparators have open drain outputs...

[@TheOffsetVolt]

Yes , they do. I do mention early in the video that the Maxim 9000 series or the LM series (from TI and ON) would be preferable ("true comparators") but this was to illustrate op amp functionality. They aren't perfect but they work quite well in some instance..