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Resistor for Nano Arduino circuit Answered

I'm trying to work out what resistor to get for the Nano Arduino circuit for this mini fridge build. From the photo it looks like a 5.6K 1%, but I have no idea what wattage? In the circuit diagram it is listed as 4.7K with no other details.


Any help would be great!

3 Replies

ggom20 (author)2017-11-29

Any 4.7k 5 % or 10 % should do.The value is not very critical.

1 percent precision is not needed it is not analog signal line.

it is a one wire communication bus witch only needs a pull-up resistor

For more information:



And btw

+1 with Downunder35m:

Using a microcomputer, digital hight precision 12 bits sensor+power switches, for a fridge thermostat looks just a bit overkilling and costly too !

Anyway learning to use an Arduino is a great occupation.

And could lead you to many more projects.



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iceng (author)2017-11-28

Downunder is correct that is what I call a pull-up resistor and can be as small as an 1/8 watt resistor.. It's job is to make sure the Mini Arduino digital input D2 has a positive voltage such that the open collector thermal sensor circuit can pull down (change_voltage) at the desired temperature..

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Downunder35m (author)2017-11-28

1/4W should do, it is just to get a clear signal from the sensor and no real power goes through there.
You can also use a simple and salvaged fridge temp sensor if you want to avoid all electronics.

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