Author Topic: Amplify 500mV 0-pk square wave to >2V for PIC MCU  (Read 782 times)

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Online mikerj

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Re: Amplify 500mV 0-pk square wave to >2V for PIC MCU
« Reply #25 on: Today at 12:06:47 pm »
it does NOT work in an actual circuit on the bench because my Function Generator cannot sink current.

Either you are mistaken or your signal generator is broken; a 50 ohm signal output that cannot sink any current would be completely useless for a signal generator.  You wouldn't be able to inject an undistorted signal into any circuit that didn't have a DC bias matching or exceeding the peak voltage of your signal (e.g. any circuit with AC coupling).

Online nctnico

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Re: Amplify 500mV 0-pk square wave to >2V for PIC MCU
« Reply #26 on: Today at 12:18:58 pm »
There's nothing wrong with my scope probe.  It is set to 10x as it should be.  See attached photo.  I also attached the scope make and model.  Nothing wrong going on there.

In my last post where I posted pics of the scope display, 0v is the bottom most line on the scope (as you may expect).
But how is the probe attenuation factor setup in your scope? Can you try to measure the speed signal with a multimeter set to DC? That should give an indication of the signal level and whether the amplitude you see on your scope is correct. It makes more sense to me when the speed signal swings between (ballpark) 2V to 10V so there is also a way to detect whether the signal is open or shorted to ground or 12V (as a security measure).
There are small lies, big lies and then there is what is on the screen of your oscilloscope.

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