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Old 09-06-2018, 11:08 AM   #1
collectors
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Default Resistor physical sizes quiry

Hi, i have some red/green signals that were meant to come with resistor for 12 volt & some were missing. No problem, i looked through my box of LED bits & bobs & had some 1k that would do the job. But i noticed that the signals that had resistors on them are around a third of the size with the same value. Are my ones just bigger or is there a reason. I am assuming larger load/wattage capabilities. But i am not sure.
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Old 09-06-2018, 11:14 AM   #2
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Hi, i have some red/green signals that were meant to come with resistor for 12 volt & some were missing. No problem, i looked through my box of LED bits & bobs & had some 1k that would do the job. But i noticed that the signals that had resistors on them are around a third of the size with the same value. Are my ones just bigger or is there a reason. I am assuming larger load/wattage capabilities. But i am not sure.
You are correct in that the bigger the physical dimensions the higher the wattage the resistor can withstand but as far as resistance is concerned it does not make any difference you can safely use the resistors you have as long as they fit in where ever they are going.

Richard
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Old 09-06-2018, 12:21 PM   #3
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Thanks Richard. These will all be under the track board. Would you know if there is a way to ID a resistors capability/capacity.
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Old 09-06-2018, 01:16 PM   #4
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Thanks Richard. These will all be under the track board. Would you know if there is a way to ID a resistors capability/capacity.
I am not sure what you mean by capability/capacity but if it's resistance you want to read then there is a colour code of bands on the body that tell its value. It is easy to learn but if you want to make life easy this website offers a a free downloadable electronics calculator which has a simple resistor identifier as well as a useful calculator to help find the correct resistor for LEDs using different voltage supplies.

https://www.electronics2000.co.uk/

If it is wattage you want then unless you know who supplied them and can get data sheets it comes down to experience. A resistor about 10mm long and 3mm diam. will probably be 1/2 Watt whilst one about 6mm long and 2mm diam. will likely be 1/4 Watt or even 0.125 Watt.

Richard
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Old 09-06-2018, 03:21 PM   #5
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Thanks, yes it was your second paragraph that i ment. Thanks for the download, i will find it handy.
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