Timeline for Understanding a coil I want to activate
Current License: CC BY-SA 4.0
9 events
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| Mar 20, 2020 at 17:01 | comment | added | Bruce Abbott | Most digital multimeters have a very slow response time, so a short voltage pulse may not give an accurate reading. The coil may produce a high voltage spike when switched off that is 'fooling' your meter. To see what is really happening you need an oscilloscope. | |
| Mar 20, 2020 at 10:36 | comment | added | Jérôme MEVEL | I think the multimeter wasn't able to measure the voltage because the activation of the relay was happening way too fast (less than a second). And without any voltage flowing in, the coil is simply a wire, thus creating an open loop. But I still don't understand how come I could measure 0.177 mA current though, I would expect current to be 0 mA if no voltage could be measured... | |
| Mar 20, 2020 at 10:33 | comment | added | Jérôme MEVEL | I think I really misunderstood how current rating on power supplies works. Your assumption makes sense to me now, if I provide 12V, considering I measured the coil's resistance at 64 Ohms, it will just draw the current it needs: 187 mA no matter if the power supply can provide up to 1A or whatever value. | |
| Mar 20, 2020 at 10:26 | vote | accept | Jérôme MEVEL | ||
| Mar 18, 2020 at 20:24 | comment | added | Jérôme MEVEL |
Cheap one: Aneng an8008
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| Mar 18, 2020 at 20:10 | comment | added | Bruce Abbott | What brand/model is your multimeter? | |
| Mar 18, 2020 at 11:49 | comment | added | Jérôme MEVEL |
Ok so I disassembled even more the device and found another relay which looks pretty much the same size. I followed the wires and one of them is linked to a 100μF 16V capacitor so probably this is the DC voltage I'm looking for. But now the big question is why is my multimeter showing OL when measuring voltage in DC mode? I'm 100% sure my probes don't touch each others
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| Mar 18, 2020 at 9:51 | comment | added | Jérôme MEVEL |
I did test again voltage in DC mode and the multimeter is showing OL all the time. I tried both in V and mV modes, I don't understand why. I don't want to go for assumptions because that would be a disaster for me if I fry the coil. This is a project I started several months ago and it would be quite hard to find another of this exact old device.
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| Mar 17, 2020 at 23:27 | history | answered | Bruce Abbott | CC BY-SA 4.0 |