Let's Make Robots!

Resistor for Servo!

hi guys!!

i have just joined the forums, how cool!

anyways.. i wanted to ask you guys a question about resistors. I already gone through all the "start here" page and when it talks about the servo it also says i need to apply a 330 ohm resistor to my board (since i don't have the "yellow thing").

but when i went to the shop the other day i found that they were selling various resistor according to W values. for example i found the 330 ohm resistor with 0.25W , 0.5W and so on.... but i don't actually know which one to use.


How do i need to calcualte the "W" i need? 

thank you! :)

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nope i don't live in uk i'm sorry :( , i live some 200kms (124.27 miles :D)  from Milan.

I just finished soldering the servo extra pin and just realized i suck at soldering :D i'll have a look at some videos on youtube.

hmm interesting! as soon as i have some time i'll go through these basics! Ah and if you need some resistors tell me :D there are lots and lots of shops (selling these things) here in singapore (in just here for a vacation). They've got a 4 storey building full of 'em.

 thanks everyone for your feedback!

Where do you normally reside? Singapore is a great place to by electronics. If you're in the UK, I'll certainly place an order!!

I don't know why I'm only seeing this now.

Watts is an expression of power. If you multiply the voltage across teh resistor by the current through it, you get a value in Watts. Make sure your resistor has a greater power rating than this value or else all the blue smoke will come out. (As you know the blue smoke is what makes electronic stuff work, so you don't want that to happen!)

Quite right - for our small signal resistors, a quarter of a watt is plenty. In fact, it's about 10 times too much, but it's expensive to make resistors accurate if they're physically small. Bear this in mind if you ever need a very very low resistance. They are likely to be physically quite large and hava a huge power rating.

I recently bought 4 ohm resistors and the lowest power rating I could find was 5Watts!! They're only ever going to be carrying a few milliamps and they were about $2 each.

yay!! that actually means i'll be able to get my servo up by tonight! (anyways i got the 0.25W one)

and you must be the really famous inventor of the YDM :) thank you for your answer!

YDM-fame - Yeah, it is like "Hotel california" for "The eagles" :D (The one hit they are always known for)

Hi, and welcome :)

This question has been up before - I cannot remember which is most common one, it is in that post - however - any will do, take the cheapest one :)

The W means Watts, (like a light bulb) whichever you get should be ok.