Multimeter or Oscilliscope

A meter is infinitely better. On a scope, you have to adjust the input level, and then count markings on the graticule. Unless you are measuring a very miniscule voltage, the markings will represent a significant jump in voltage, so you'll always be wondering whether the deflection is closer to the half way point between graticules or the next one up or next one down.

A multimeter is intended to measure voltage. You get a much nicer scale with lots of markings. And given that most multimeters these days are digital, no parallax as you try to decide where the needle is resting.

The only place where an oscilliscope is better is when measuring complex waveforms, because that will likely mess up the readings on a multimeter. On a scope, you see the waveform and can take it all in. Of course, nowadays lots of scopes have better frequency response than a multimeter, so they are generally better than the average multimeter to measure AC above a fairly low frequency. But in both cases, you'll have to puzzle over which marking on the graticule the waveform reaches.

For DC, neither of those exceptions come into play. There is no reason to use a scope to measure DC.

Why the same voltage reads differently on two pieces of equipment can vary quite a bit. Sometimes it's parallax, you can't read exactly where the needle is pointing. Sometimes it's because the units are not properly calibrated, or calibrated to unequal voltage "standards". Sometimes it's because the unit doesn't have high impedance input, so it loads the circuit down and thus changes the reading. Sometimes it is because a given piece of test equipment can't be as accurate as another.

Michael

"jason"

** What " oscilliscope " IS that then ??

A real one with a CRT ??

A virtual one in software ???

A digital one with on screen voltage and frequency display ????

Do try to be more careful when you throw terms around.

...... Phil

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Thank you very much!

The multimeter is much more accurate, by around an order of magnitude (10 times). It's the proper tool for the job here.

A typical low end digital multimeter will have say 0.5% or better basic DC volts accuracy. An oscilloscope on the other hand (even the really expensive ones) will only have around several percent basic accuracy on the vertical channel at best.

The exception to this are oscilloscopes that have a special digital multimeter modules built into them.

The product specs will tell you everything you need to know.

Dave.

"Michael Black"

** Except for the VERY important reason of establishing that the voltage IS in fact pure DC and does not have an AC signal superimposed.

Cos you often cannot easily tell that with a multimeter.

....... Phil