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I am setting up my home security system. It calls for a 5.6 ohm resistor at the end of the line with smoke detectors. Does it matter what wattage? Can I get by with 1/4 watt?

JRE
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C.W.
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1 Answers1

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I suspect it's supposed to be 5.6kΩ, because that's a standard.

EOL resistor in fire alarm systems

1/4W should be okay since voltage will be 12V or so (P=E²/R, thus 144V²/5600Ohm ~ 26mW).

As user253751 mentioned: the reason that end-of-line resistors are used is so that the alarm can sense whether the wire is broken. If the wire is broken the resistance will change (usually to zero or infinity)

Thomas Weller
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Spehro Pefhany
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    Aside: The reason that end-of-line resistors are used is so that the alarm can sense whether the wire is broken. If the wire is broken the resistance will change (usually to zero or infinity) – user253751 Mar 08 '23 at 20:42