Multimeter recommendation?
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@nca78 for such a low current the best bet would be EEVblog's uCurrent
https://www.adafruit.com/product/882@alexsh1 yes and no. I measure at 3.3V then run my low power nodes on a button cell so below 3V voltage, so I measure current a bit higher than the real one when node is on battery and I'm sure the battery life I calculate will be met. I don't need an ultra precise measurement I just need to know if I'm in the expected range or if something is wrong.
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@alexsh1 yes and no. I measure at 3.3V then run my low power nodes on a button cell so below 3V voltage, so I measure current a bit higher than the real one when node is on battery and I'm sure the battery life I calculate will be met. I don't need an ultra precise measurement I just need to know if I'm in the expected range or if something is wrong.
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@nca78 Sometimes I need to measure current as low as 2uA. I do not think I can do that with my multimeter. So uCurrent is a good investment from my perspective.
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@alexsh1 https://www.openhardware.io/view/380/Micro-nano-ampere-meter-double I think it is a good alternative from a cost perspective
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I already had a Fluke 72 (old one with no current range below 10 Amps).
So for better accuracy, I purchased an HP 3478a digital multimeter on eBay for about $140. It gives me all the accuracy I want (but probably don't need) and has 1 µA resolution (accuracy is somewhat less but for tweaking battery usage stability makes it usable.
Of course it is not as portable as it needs mains power.
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I just realized I forgot to report back. I bought a multimeter called pm18c. The temperature sensor is very fragile - broke almost immediately. But the rest works well. I still use my old small multimeter a lot though, the pm18c is a bit bulky.
Big thanks to everyone for the input!
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Aneng an8009 or similar is still a really good buy, 9999 counts is not something you get usually from cheap meters
@gohan said in Multimeter recommendation?:
Aneng an8009 or similar is still a really good buy, 9999 counts is not something you get usually from cheap meters
I bought one and I don't suggest to buy it for MySensors projects.
Plugs for mA and uA are separated, and it makes it a pain to measure current consumption in battery powered nodes, you have to unplug/replug the wire to change scale between the 2 modes. When node is sleeping and you are in mA modes you don't see anything. When you are in uA and node is waking up it doesn't have enough current going through the multimeter and it resets. -
It is a common issue I see in these small cheap meters. There is always the openhardware current meter for what you are suggesting
@gohan said in Multimeter recommendation?:
It is a common issue I see in these small cheap meters. There is always the openhardware current meter for what you are suggesting
Sure but there are other multimeters with a common plug between mA and uA so you can just change range on the selector and you don't have to cut the power to your node during that switch.
