DC range suggestions for Metro M4 differ between pdf and web

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PureWeen
 
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DC range suggestions for Metro M4 differ between pdf and web

Post by PureWeen »

The webpage says https://learn.adafruit.com/adafruit-met ... rlift-wifi
Power the METRO M4 with 7-9V polarity protected DC

But the PDF on Page 17 says
https://cdn-learn.adafruit.com/download ... 1630793183
The DC Jack is a 5.5mm/2.1mm center-positive DC connector, which is the most common available.
Provide about 6V-12V here to power the Metro.

Or am I misunderstanding what it's saying the 6V-12V's applies to?

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Re: DC range suggestions for Metro M4 differ between pdf and

Post by adafruit_support_bill »

The device will run on 6V-12V. But 7V-9V is a better working range if you have much external circuitry connected.

At 6V, you are pushing the lower limits for stable 5v regulation. 7V gives the regulator a little more 'headroom' to produce stable 5v power for any connected devices that need it.

And anything over 7V needs to be 'burned off' as heat by the linear regulator. At 12v, you are making the linear regulator work pretty hard to do that (not to mention wasting nearly 60% of the power in the process). So if you need to power much in the way of external circuitry, it is best to keep within the 7V to 9V range.

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Re: DC range suggestions for Metro M4 differ between pdf and

Post by PureWeen »

Makes sense thank you!! I'm powering a few LED Flex strips so was planning on just using one 12 V source for it all. It's good to know I won't fry the thing with 12V so I can at least be safely inefficient while getting it all coded and then use better source once I'm done.

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