On Mon, 01 Jan 2007 19:48:15 -0500, Jamie
>> kontiki wrote:
>>>Hi, does anyone know where a reference table of parallel resistors
>>>could be found?The table is very useful for quick accurate resultant
>>>resistances (to two places of decimal), the tables I've got are from
>>>Practical Electronics Jan. 1990? and have faded to the point of being
>>>unusable.Most non-standard resistance values are easily ascertained
>>> e.g.for 17 ohms->75//22
>>>quickly and easily!
>>> with thanks,
>> thank you for your replies....the "math" is fine,....
>> lets say I want to shunt a 120k res. to get a
>> 15.6k how long does it take to find the required value? a table is much
>> faster ,and if you are limited by values "at hand" again an alternative
>> pair is easily/quickly chosen.This is useful for establishing the
>> practical effects of temperature compensating resistors and
>> I tend not to fire up the pc each time I need to do the math...
>You just reverse the standard method..
>(120K*15.6K)/(120K-15.6K) = 17.931K which is what you need.
>Personally i like this one.
>1/(1/15.6K- 1/120k) = 17931;
> I can hit the inverse( reciprocal ) key on me calculator at the
>end instead of starting it off with a 1/(... , this saves in a 2 key