Precision Resistors How to

[multi-volti at MULTI-VOLTI.COM]

I forgot to take my technique one step further.

Looking at the 1% chart,

I have 10k and want 9876. I need 796541. I can find 820k

10k||820k = 9879.5

100*(9879.5-9876)/9876 = 0.036%

Remember to pay attention to power AND voltage rating.

Don't put 1000V across a resistor that's rated at 250V regardless of what
fraction of it's power rating you might be dissipating...it'll probably
change value.

Use series/parallel combinations if you need to increase voltage rating.

Murray

Murray
----- Original Message -----
From: <multi-volti at multi-volti.com>
To: "Charles Seitz" <cseitz at ENTER.NET>
Sent: Thursday, May 15, 2003 10:19 PM
Subject: Re: Precision Resistors How to


> 1/(1/known -1/unknown) = 1/desired
>
> This is derived from the alternate method of finding parallel resistors -
if
> you have three in parallel for example, R1R2/(R1+R2) doesn't work, so you
> use
>
> 1/ sum of inverses.
>
> example
>
> you have 10k and want result of 9876. What goes in parallel with 10k to
give
> 9876?
>
> 1/(1/9876 - 1/10000) = 796541.61
>
> Murray
>
>

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