1/8 watt resistors for 2xnes to snes controller mod

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gamemasterful
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1/8 watt resistors for 2xnes to snes controller mod

Post by gamemasterful » Sat Apr 03, 2010 4:43 pm

I'm following this guide http://www.extremetech.com/article2/0,2 ... 807,00.asp" onclick="window.open(this.href);return false; to build the controller, but accidentally got 1/8 watt resistors. Is this still fine? The whole system is running on a regulated 5 volts.

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OMGpedobear
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Re: 1/8 watt resistors for 2xnes to snes controller mod

Post by OMGpedobear » Wed May 05, 2010 1:06 pm

link not working, unless they are on a direct power line, pulling more than a few amps it should be fine. What wattage where they supposed to be ?

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Re: 1/8 watt resistors for 2xnes to snes controller mod

Post by jdmlight » Wed May 05, 2010 1:30 pm

OMGpedobear wrote:pulling more than a few milliamps it should be fine.
Fixed that for ya. :wink:

They were supposed to be 1/4 watt resistors. 1/8 watt is probably fine. What I recommend doing is building it with the 1/8 watt resistors, then try it out. If the resistors start getting hot, you probably need to use 1/4 watt resistors. Otherwise, you'll be fine.

My mathy reasoning behind saying it's probably fine:
Spoiler:
A 1/8 watt 10k ohm resistor can handle 3.5mA going through it. I calculated this by taking P=I^2*R, moving around the variables using algebra (ended up with I=sqrt(P/R) ), and plugging in your numbers. Based on that same formula, a 1/4 watt 10k ohm resistor can handle 5mA. 3.5 and 5 mA aren't much different, so I suspect you'll be fine.
Cool guide by the way, I bookmarked it in case I decide to make a SNESp. :D
--John (and please call me John, it's really weird to be called by my username)
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OMGpedobear
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Re: 1/8 watt resistors for 2xnes to snes controller mod

Post by OMGpedobear » Thu May 06, 2010 11:10 am

back in the days when i used to do model rocketry i used 1/8 w resistors to ignite the motors, and i am sure you can pull at least 2 amps through them before them catching fire and easily half an amp safely. Mind you im not sure using them as igniters is the best experience to draw on, any ways thanks for the correction :).

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Re: 1/8 watt resistors for 2xnes to snes controller mod

Post by jdmlight » Thu May 06, 2010 11:28 am

OMGpedobear wrote:i am sure you can pull at least 2 amps through them before them catching fire and easily half an amp safely.
I'm sure you can draw a lot more than 1/8 watt through an 1/8 watt resistor before it catches fire. :lol: Typically manufacturers rate these wattages so that the resistor won't heat up much (if at all) when pulling its rated wattage. You can certainly pull more than the rated capacity through a resistor, I have many times. Presumably if you push through more than the resistor's rated capacity the resistor will wear out faster. (But this is similar to the argument about overclocking: supposedly overclocking will reduce the life of your processor; however, most people aren't going to care because they'll upgrade their computer before it would ever matter.)

Also, it definitely depends on the resistance value of the resistor. If you plug a 100 ohm resistor into the formula I had before, it can draw up to 35 mA according to the official spec.
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Re: 1/8 watt resistors for 2xnes to snes controller mod

Post by OMGpedobear » Fri May 07, 2010 10:29 am

oops, over looked the resistance aspect, of the resistor :facepalm: .

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