If you have a chance, please look at the following PDF file, page 11:
http://www.tube-tester.com/sites/nixie/dat_arch/ITT_app_notes.pdf
They're calculating the RMS value of current through a NIXIE tube driven from a full-wave rectified supply. Since the tube "strikes" at a certain voltage, and then drops out of conduction when the waveform drops back to that voltage, the calculation of the RMS voltage has to be done via an integration of the voltage between the starting angle \(-\theta\) and the stopping angle \(\theta\). What I don't understand is why they also evaluated R between the limits of \(-\frac{\pi}{2}\) and \(\frac{\pi}{2}\). Since the equation for RMS current is simply \(I = \frac{Vrms}{R}\), shouldn't the R just move outside the integral as a constant? Thanks for any insight!
http://www.tube-tester.com/sites/nixie/dat_arch/ITT_app_notes.pdf
They're calculating the RMS value of current through a NIXIE tube driven from a full-wave rectified supply. Since the tube "strikes" at a certain voltage, and then drops out of conduction when the waveform drops back to that voltage, the calculation of the RMS voltage has to be done via an integration of the voltage between the starting angle \(-\theta\) and the stopping angle \(\theta\). What I don't understand is why they also evaluated R between the limits of \(-\frac{\pi}{2}\) and \(\frac{\pi}{2}\). Since the equation for RMS current is simply \(I = \frac{Vrms}{R}\), shouldn't the R just move outside the integral as a constant? Thanks for any insight!