Comment summary #33
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Comment 321 ... 330
| date | article | author | comment |
| 28 jan 2016 10:46:22 | Arduino wattmeter | Allan Lind | Does this device measure power flow in both directions so it can be used for solar grid tie installations? If not is is possible to adapt it to do this? |
| 27 jan 2016 13:35:51 | Magnetic permeability | kaka | Thank You!! |
| 27 jan 2016 10:06:06 | Arduino wattmeter | Freddy | The input offset voltage of the LF411 is way too high. 500μV is stead of the recommended 5μV. And also the input bais current is too high. Be carefull with the high voltage. |
| 27 jan 2016 03:03:45 | Arduino wattmeter | Azzelle | Ahh I see. Thank you for that, now I understand. I am using a 220Vrms source and load of 40W bulb. The current opamp I am used is LF411, dual supply +-4.5V. The COM value has changed to 0.637V instead of 0.55V BTW, the R1 I used is 8.2M and R3 is 10m. Thank you. |
| 26 jan 2016 23:34:46 | Magnetic permeability | Freddy | It is best to take Rv as large as possible. In practice the value will be determined by the available voltage supply. So, if you have a 0...30 VDC power supply, the upper limit of 30 V and the maximum current will determine the resistor Rv. |
| 25 jan 2016 19:21:06 | Magnetic permeability | kaka | Thanks for the answer! I dont understand how i get the DC - circuit sizes. I know I have to calculate Rv = V DC /I DC and I have to change I DC . But I dont know how big V DC should be and thatswhy I cant get the Rv? |
| 25 jan 2016 19:12:33 | Magnetic permeability | Freddy | It is the same. |
| 25 jan 2016 16:34:44 | Magnetic permeability | kaka | If calculate the AC-Current with the help of B, I wouldnt know the voltage AC or is it the same as in "Determine the permeability"? |
| 25 jan 2016 16:33:54 | Magnetic permeability | kaka | Ok I understand it now how to calculate B, thanks! |
| 25 jan 2016 16:04:18 | Magnetic permeability | Freddy | The inductance B can only set approximately due to the hysteresis of the core. Use te equation B=(μc*I)/(lc*N). The resistor Rv is calculated by Rv=V/I. |