i have a AC source of voltage V and some frequency f, a resistor and an inductor in series. i'm trying to use VIZ, setting Z (R+X(L)). but for the Voltage, do i use peak to peak or rms voltage? and explain to me the reason you chose that one over the other one in this situation. also for the current i will be measuring in series, how should i measure this for an AC circuit? i know multimeters have AC or DC options for voltage reading, but for current, seems like theres only a DC option. any suggestions with this issue? thnx guys
there are plenty of methods available for calculation of inductance u can use Maxwell's inductance,Maxwell's inductance-capecitance bridge,hay bridge,Anderson bride and many more it is very simple rather than theoretically u should use RMS value in any mode current is depend upon load connected.
You have to use RMS and assume a sine wave. The 2 pi bit in Xl2piFL requires this. Good luck the rest is correct.
Hi pLaSmA, first and foremost point is AC whether voltage or current cannot be measured as the average for one full cycle would be zero. So ac will be first rectified and then measured. Secondly, as ac voltage or current is measured it rms value alone will be measured not its peak value. Third point ie an important point to be noted. Impedance Z will not be the mere sum of resistance R and inductive reactance XL. No way we can add them straight away since as per phasor relations both will be perpendicular to each other. Hence Z ./ R^2 + XL ^2 So you must be given the rms values of voltage and current. If peak is given then you can get rms right from peak by using the familiar relation I rms I peak / ./2, same way with V. Now knowing Z and R (it will be given), you can compute for XL. Knowing XL 2 pi nu L and using the values of nu as (usually) 50 Hz, you can get the value of L ie inductance of the coil.
Use RMS values Xl 2 x pi x F x L Z Sqroot of (R^2 + Xl^2) actually complete equation Z Sq Root of ( R^2 + (Xl - Xc)^2 ) for RLC circuit but in this case Xc zero Then V IZ More expensive multimeters have many functions including True RMS values and AC or DC current settings calculate Z as above measure Voltage RMS and then calculate AC current if you cannot measure it
Use rms Voltage values because that is what a standard Volt-Ohm meter measures. The source must be a sine wave for the following procedure to be valid. Measure Voltage (Vr) across the resister and use this to calculate the total current. Total current (It) (Vr) / (R). I think the calculated ac current will be more accurate than the measured current if you are using a standard Volt-Ohm meter for measurements. Calculate total impedance (Z). (Z) [source Voltage (Vs)] / (It) Measure the Voltage (Vl) across the inductor. Calculate the inductive reactance (Xl) of the coil. Xl (Vl) / (It) Calculate the value of the inductor using (Xl) 2pi fL. L (Xl) / 2pi f Note: Most Volt meters can not accurately measure sine wave Voltages at frequencies above 50-60 Hz. Therefore your calculated value of inductance will probably not exactly match it`s actual value.
