Sense resistor

[Hex173t]

I need a low ohm sense resistor for a battery charger IC (Max713) for charge current feedback.  It works out that I need .694 ohm.  I don't have this value in a real resistor, I was thinking of using a length of aluminum 24 awg wire instead.  I can't think of why this wouldn't work.  Is there a good reason not to do this, like it would cause some technical issue?  Please keep in mind this is on a bread board and temporary.

Thanks in advance
Bill

[BravoV]

Get three resistors which are one 1.2 Ohm and two 3.3 Ohm, put them in parallel and you will get a resistance approx. 0.694 Ohm which is quite close to what you need.

[grenert]

At only 0.02567 ohms per foot, you'd need a lot of wire to reach .694 ohms.  A lot more than you could deal with on a breadboard (>20 feet).
Parallel resistors is a great solution.

[Rufus]

It works out that I need .694 ohm.  I don't have this value in a real resistor

0R68 is an E6 value and only 2% out.

[ejeffrey]

If you have to use a wire a resistive wire like nichrome is better.  It will be shorter and have a lower tempco than aluminum wire.

[Hex173t]

Thanks for all the ideas.    I didn't mention but I only have (5) 12 ohm and (10) 10 ohm and will give .706, acceptable I think.  And I did a quick test of 6 feet of wire and it works out to be .176 ohm, so I need 24 feet of wire which I don't have. Bottom line, whether I go with with nichrome or fixed resistor combos, I alot of wire, alot of resistors or need to do some shopping.

I do appreciate the replys, I didn't know about nichrome.
Bill

[robrenz]

I have purchased nichrome from here several times with good success.  they have assortments also.
http://stores.ebay.com/Wires-Store/_i.html?_fsub=657165