Resistors?

[DeAd]

Hey I do alot of hobby electronics and i would go broke if i tried to buy every part i needed. What i do is find free junk radio's, tv's, ect. and dis-assemble them for the usefull parts. Getting a de-soldering iron($5.00) makes it very easy. And there is no paper trail of you buying parts. Lots of knowlege can be gained by doing this. There is great potential here because in time you will be able to scavange whole circuits, You don't have to know how to make an IR modulator - you just need to know how to take it out of the remote control. an example is for guided rocket systems: To try to make a proportional control system that is small enough to fit on a small rocket is impossible(for me anyway) But you can take the lense control system from an old cd-rom drive and use it with very little modification. Its very small, uses mili amp current, and is proportional.
For your original question of needing 100 ohm resister if your working with analog electronics any resister thats close to 100 ohm may work, just try any resisters you have you may get lucky. Or you could put 2 50 ohm togeather. It is my experience that {in most cases} analog electronics are not all that picky.

[nme]

Do you mean to control fins for the rocket? (Soz was jus curious about this example.
Your mostly right about analog not being to picky, unless you cross a distinct line or are looking for a particular effect (such as in sound-effects).

[DeAd]

hey I've found it easier to leave guide fins static ( I use those for stability in flight and to get the rocket out of the launch tube and electrical path for launch system) and use a control surface (airfoil) at center of gravity on rocket body. Its like using leverage, a little force is used to control a larger force. one control surface is easier than 3 or 4 on the fines. Its less things to go wrong.

[drbroccoli]

100 is usually really common. Radioshack is good.

[TheFallen]

heh, I'm trying to get hold of some o.5 ohm resistors for motor sensing (as in the voltage across them is proportional to the current in the motor windings) For stepper motor drivers, namely an L298/L297 combo, anyone know about good suppliers? I can find them in the USA, but not so much in the UK.

They can't be wirewound and it'd be REALLY helpful if they weren't surface mount.

[drbroccoli]

There is a site called futurlec.com
I've ordered a lot from them. They seem fairly reliable, but can take a month to ship. They're located in Thailand I think.
They sell 1 ohm 5 watt wirewounds. You could get two and put them in parallel.
Would putting two 5 watt resistors in parallel result in a 10 watt resistor?