EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Nhan95 on May 11, 2015, 01:22:10 am
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When I use analog oscilloscope in the experiment, sometimes I work with sine wave or square wave, my teacher asked me to choose DC mode for channel 0 and channel 1 or I will face with wrong result. Uhm, I feel confused :( . Could you help me when we use DC or AC mode?
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If the sine wave or square wave has a DC bias either pos. or Neg, then you need to be DC coupled or you won't be able to see the offset. AC coupling will remove any DC biasing of a waveform.
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Another way understanding it is to see what the switch actually does. When I was younger, I could only afford old tube based 5MHz bandwidth oscilloscopes, which were pretty horrible but how they worked was obvious just by looking. The AC coupling switch simply put a 0.1uF capacitor in series with your probe lead. That way all DC was blocked to the vertical amplifier.
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Before asking for any help with basic use of an oscilloscope, everyone should watch the video in this thread.
https://www.eevblog.com/forum/beginners/oscilloscope-training-class-(long)/ (https://www.eevblog.com/forum/beginners/oscilloscope-training-class-(long)/)
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Or you could download this document from Tektronix :)
http://info.tek.com/www-xyzs-of-oscilloscopes-primer.html (http://info.tek.com/www-xyzs-of-oscilloscopes-primer.html)
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...my teacher asked me to choose DC mode for channel 0 and channel 1 or I will face with wrong result.
I'm thinking - is the teacher teaching you these things? Did you ask the teacher? Just thinking out loud on this end. ???