Offset sine wave

Thread Starter

Tobias

Joined May 19, 2008
158
Thanks for helping out on the comparator, it works great. I plugged my scope into another vehicle to look at the output of the front wheel speed sensors. The sensors are on a 2009 Chevy Diesel pickup, in case anyone is wondering.

When I first hooked up the signal wasn't on the scope. So I broadened the y-axis to 5v/mark. The signal is offset around -3v. Still learning how to correctly use my scope I started to play around with the coupling setting for the channel. The coupling was set to DC, so then I changed it to AC and the output was then centered on 0v.

I looked up 'scope coupling' on the internet and found a handy site. Here it is for all others as new to this as I am.

http://oscilloscope-tutorials.com/oscilloscope/controls.asp

Anyways, I am going to get the pickup tomorrow to validate my findings. But, if this is the case, where the sine wave is offset a -3v, whats the trick to measuring the peaks that are above the -3v? I am playing around with an op-amp and setting it up as a 'sum op-amp'. I am adding 3v to the -3v offset sine wave that I can get with my scope and the results and not what I was expecting.

Thanks
Toby
 

Audioguru

Joined Dec 20, 2007
11,248
Modern cars use a positive supply. Your 'scope is messed up since it shows -3V.
Connect the input of the 'scope to 0V and the trace should show 0V. If it doesn't then adjust the vertical position control.
 
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