| ??? 05/31/05 15:02 Read: times |
#94147 - DC+AC RMS Responding to: ???'s previous message |
You're right: it's not.
The RMS value is the DC equivalent that dissipates the same heat in a resistor. RMStotal = sqrt(ACrmscomponent^2 + DCcomponent^2) (The DC value is, of course, its 'RMS' value.) In a cheap AC voltmeter (moving coil or DVM), they sample the peak (diode + capacitor) and show 0.707 of it (forgetting the diode drop). This is great, so long as you're measuring a pure sinusoid. Anything else will probably be incorrect. Hence the, now fairly common, 'TRUE RMS' DVMs that properly compute the RMS of measured AC voltages in their frequency range. On the one I have (FLUKE 8060), you still have to switch to DC and measure any offset, before doing the above calculation... Dave |
| Topic | Author | Date |
| RMS Calculation | 01/01/70 00:00 | |
| Going back to basics... | 01/01/70 00:00 | |
| How Many Samples Per Second? | 01/01/70 00:00 | |
| Square Root Algorithm | 01/01/70 00:00 | |
| RMS for sinusoidal signals | 01/01/70 00:00 | |
| Clarification | 01/01/70 00:00 | |
| I beg a question... | 01/01/70 00:00 | |
| Full o' holes | 01/01/70 00:00 | |
Bang on target... | 01/01/70 00:00 | |
| thats true... | 01/01/70 00:00 | |
| RMS Value | 01/01/70 00:00 | |
| Please elaborate more... | 01/01/70 00:00 | |
| Elaboration | 01/01/70 00:00 | |
| Correction | 01/01/70 00:00 | |
| DC+AC RMS | 01/01/70 00:00 | |
| DC contribution to total rms value | 01/01/70 00:00 | |
| Thanx Anywayz... | 01/01/70 00:00 | |
| square root by Newton's Rule | 01/01/70 00:00 | |
| Lookup table | 01/01/70 00:00 | |
| better option...as of now | 01/01/70 00:00 |