1.1107 being the form factor of a Sine wave. If the DMM is in AC mode (Averaging AC Mode). The DMM reads +2.5V, since the RMS value of the 5Vpp Unipolar Square wave = 2.5V 50% duty cycle. If the DMM is in AC mode (True-RMS AC-Mode). At very low frequency probably flicker effect or inconsistent reading may occur, since the wave form value may change during the dual-slope conversion time of the DMM- ADC.
#RMS VALUE OF BIPOLAR SQUARE WAVE UPDATE#
Most current DMM's have a display update of 3 readings per sec. The DMM in DC-Mode reads the mathematical average of the input wave form, over the timeline, which is +2.5V. (Not a diff parameter) Answer for the above special case & the varying cases specified in 5,6 items:- A. # Item-4 is simply another way of seeing item-3. DC Offset : +2.5V DC offset, on a bipolar +/- 2.5V Square wave (Vpp = 5V) 5. If DMM in AC Mode, then is it an "Averaging" AC-Mode or "True-RMS"? The special case OP's question is as below, for earlier 6 factors. Is the DMM configured, in DC mode or AC Mode? 6. Else how much DC offset is there on the case-3 waveform. If the waveform is bipolar & symmetrical across the zero-line. If it is a Square waveform what is the duty cycle % 3. Shape of waveform (Square/ Sine/ Triangular/ Irregular). I am answering for a general case first, & then narrowing to the specific case asked by OP. DMMs: What you see in a DMM, is a single representational value, which is computed depending on following factors. So there is not much to say any more about it. SCOPE: In a scope you will see the actual (instantaneous) waveform value in real-time always. But got refined when I started working with PSPICE Tools & circuit simulations, to better my understanding. I got a better handle on this after I worked with True RMS meters along with older conventional Averaging DMMs. I am also an electronics hobbyist and engineer, & pondered this same issue some years earlier, when working with various DMMs & scopes. This is an old post, & IanB has answered it somewhat. Earlier I thought when you apply pwm to a LED it just flickers and thats why it appears as dimmed or brighter. 100ms gate time? When a pwm wave is applied to a resistor, to calculate voltage drop, do you consider the pk-pk voltage or average voltage as input voltage? Can you please point me in the right direction? I am little confused as wave always have 5v and 0v levels but the multimeter reads an entirely different reading. I was wondering how it works? How multimeter averages this? Is there a sample interval which is constant across all the multimeters? e.g. Multimeter on the other hand just showed me 2.4-2.5v and nothing else. Oscilloscope showed all the measurements, pk-pk, duty cycle and frequency and average voltage too. I fed it to an oscilloscope and a multimeter. I generated a 5v pk-pk square wave with 50% duty cycle. Using various mathematical operations it can determine duty cycle, frequency and voltage levels etc. As per my understanding an oscilloscope takes multiple samples every second and then plots them on the the screen.
![rms value of bipolar square wave rms value of bipolar square wave](https://electricalacademia.com/wp-content/uploads/2018/07/Figure-8.png)
I am trying to understand it by finding analogy with an oscilloscope. I am unable to understand how a multimeter measures pwm voltage (average voltage).