Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
In short, the RMS value will be used with relation to sine waves which are AC-coupled to eliminate the effect of DC bias, whereas the True-RMS value will be use to measure the RMS of complex waveforms, such as sine waves chopped by a triac, triangle or square waves ..
First Voltmeters givesyou RMS value in thefollowing form: peakvalue *0.7071 wich is true for a perfect sinusoidal wave form, but not true for another wave form.
TRUE RMS gives a real RMS value for any kind of wave form.
RMS vs. true RMS comes from the method used to measure RMS voltage.
Some (simpler or older) instruments have detectors that measure average value of the voltage but the display is calibrated to show RMS value with assumption that input signal is sine wave.
Of course, this instrumentst will give correct reading only for sine waveform since the scaling factor depends on the form of the input signal.
True rms instruments give correct rms value of the input voltage (within specified frequency range and crest factor) They are usually made either by analog circuit that calculates the rms value , or they use thermocouples.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
