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Hello, I'm about to buy some resistors, I would like to know which values do you recommend that are good to have to make tests etc...

I know I need values between 50 - 500 ohms for example for LEDs, I also need 4.7k (or 10k?) ohms for pull ups for my DHT22/DS18B20 sensors..

But appart from those values, which ones are good to have ready? I probably don't need values like 1 ohm, or 10 M ohm, right? Please suggest common values for arduino projects.

Thanks smiley
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Nice Question,

I grabbed a bulk mixed pack rom my local electronics store the other day. This is a question heaps of people wopuld find useful. Same for Caps possibly?
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 Whenever I buy resistors I buy 1, 10, 47, 100, 220, 470, 1k, 5.6k, 10k, 56k, 100k, and 1m. I've found a use for all of them.
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I use three values predominantly: 1k, 10k, and 100k.
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There do seem to be just a few values that address the vast majority of my needs!

330Ω, 1K, 2.2K, 4.7K, 10K. 1/4W or smaller, 5% or better.

Capacitors: 100nF ceramic, 10µF electrolytic, then some larger electrolytics for filtering, value is usually not super critical, whatever you can find cheap, e.g. 100µF, 220µF, 330µF, 470µF, etc. All should be 16V or better. As for the 100nF caps, get them by the hundred, they're best with 0.1" lead spacing, I like the multilayer ceramic type (MLCC), X5R or X7R spec is best.
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Thank you all smiley-wink
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Capacitors are slightly different.

I use a lot of 4.7u/.1uf, as well as 12pf/15pf/22pf (for crystals).

Anything else would be highly application specific and hard to say.
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Mostly what I use is 220, 470,1k,10k,
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My advice is buy a resistor kit - much better value than buying resistors individually. Something like http://www.rapidonline.com/Electronic-Components/MR25-Metal-film-resistor-kit-65199 or http://www.ebay.co.uk/itm/1-4W-Metal-Film-Resistor-Assort-kit-1000-pc-50-values-/220719309028?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item3363e560e4.
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On the subject of leds and resistors, I recently sat and soldered resistors onto a handful of leds to save messing around when I need to use them.

Why don't they leave the factory like that... maybe in a few flavours for different voltages.

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My local supplier just started selling this.

Previously I bought one of these.
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On the subject of leds and resistors, I recently sat and soldered resistors onto a handful of leds to save messing around when I need to use them.

Why don't they leave the factory like that... maybe in a few flavours for different voltages.

Because the resistor value you need depends not only on the voltage of the supply but also on the current you want to drive them at. You may want to drive the same LED at different currents, for example if it is multiplexed with other LEDs.

However, you can get LEDs with built-in series resistors, for example http://www.maplin.co.uk/12v-3mm-leds-35738.
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On the subject of leds and resistors, I recently sat and soldered resistors onto a handful of leds to save messing around when I need to use them.

Why don't they leave the factory like that... maybe in a few flavours for different voltages.



Because manufacturing and selling raw resistors and leds is a very high volume very low margin commodity market. Making and selling LEDs with either a internal or soldered external resistor would turn it into a low volume speciality component and would have to have a much higher margin to make and sell profitably. I know that Radio Shack use to sell a two lead +5vdc only led that had a internal resistor installed inside the led package, also had one that blinked automatically. Not sure if they still carry either of those now.

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Unless I'm buying some weird value etc., I almost always buy resistors in lots of 100. Even from the top-shelf distributors, they're usually only a penny or two each in that quantity, and I probably end up with a lifetime supply or nearly so smiley-wink
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From Amazon: 860 resistors for 17.99: 10 X 86 values from the E12 List  (Most Common resistors)
http://www.amazon.com/Joe-Knows-Electronics-Value-Resistor/dp/B003UC4FSS/ref=pd_rhf_se_s_cp_4

There was another kit for 29.99 that was 4300 resistors, I bought one...
Still can't find a place for all of them, I could split them into 4 assortments all the same and one would be all I'd probably use.. Ever.

Bob
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