Comment summary #46
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Comment 451 ... 460
| date | article | author | comment |
| 22 aug 2014 21:18:32 | Arduino wattmeter | Freddy | The voltage on A6 is approximately +0.55 V relative to the Arduino ground. This is half the reference voltage. Yes, the current signal goes inverted (by the opamp) into the Arduino. But it is directly after the ADC-convertion inverted again by software. You can find the line: adcVal = -adcVal; in the /*** Interrupt routine ADC ready ***/ ISR(ADC_vect) { under /*** Current measurement ***/ |
| 22 aug 2014 20:02:39 | Arduino wattmeter | Barber | I am working on a modification of the shunt circuitry to measure the current. I have a question about the input A6 polarity. Based on the schematic, the current signal goes into the Arduino "inverted" by the LTC1050. Is this compensated for within the software? If not wouldn't the current be 180 degrees out of phase with the voltage? |
| 22 aug 2014 15:39:42 | Current transformers | Freddy | Did you use the right terminating resistor on the secondary side of he current transformer? The manufacture describes often a specific resistance value for it's transformers. Otherwise, terminate the secondary side with a low as possible resistance. |
| 21 aug 2014 18:53:39 | Current transformers | sabahat | Dear Sir I have a problem in using ct, I am using 100/5A CT. as the current through ct increases, it distort the wave shape, making difficulties in zero detection. can you please help? |
| 07 aug 2014 12:38:29 | Multimeters - measurement deviation | Freddy | The equation as it stands is correct. I checked the documentation again from both Fluke and Agilent and it tells me the same. When this article was written, the equation was also empirical checked with various waveforms. |
| 07 aug 2014 07:34:18 | Multimeters - measurement deviation | John Lam | I am confused with equation 1. What I remember is that if the supply contains both AC and DC, then Vrms = SQRT [ DC^2 + (AC^2)/2 ]. Is yours a typo mistake or for somthing else? |
| 04 aug 2014 08:40:47 | Theory and Definitions | Raghavendra H R | Thank you sir .. you are thinking is right. it was more helpfull to me for doing M.Tech project. it was simple method and I got accurate answer. thank you lot. |
| 03 aug 2014 21:18:39 | Theory and Definitions | Freddy | Off course the numbers must be negative, I've corrected it. I was thinking positive ;) The width of the time chunks is a choice. I choose 1 ms to reduce the number of calculations. But for more accurate calculations you can choose for example 0.2 ms intervals, but the number of calculations is than five times as high. |
| 03 aug 2014 20:59:38 | Theory and Definitions | Raghavendra H R | Thank You So Much For your Reply.But I've Two Doubts regarding your calculation. 1)In the Graph There is negative Power but you have taken positive for the calculation. 2)Regarding the time that you have taken for each chunks is 0.001s, can you explain why is it so? |
| 02 aug 2014 19:41:50 | Fast Lux meter | Josh | Ok, I'll let you know how it goes, thanks! |