ORIGINAL MESSAGE:
On Sun, 4 Nov 2012 07:04:09 -0800, VE7RF wrote:
> I checked all 300 of em..and all
>300 of em were exactly 200 ohms on the low side..= .2% tol. For an eq
>resistor,
>the value itself is no big deal, anything from 90-110K is fine. What you
>want is for
>them to all be the same.
REPLY:
You got lucky on that batch and here's why.
When manufacturers make resistors,they make a huge batch of them. They then
cherry pick out the tightest tolerance ones and sell them at a premium price.
Then they next cherry pick out the next lower tolerance and sell at a lower
price. Then they cherry pick out the next lower yet tolerance, etc, etc.
This means that the second and third cherry picking gets both ABOVE and BELOW
the tighter tolerance units. You were lucky to get all of yours on the low side,
but next time they could have been mixed high and low or all high.
The point is you must still individually check each resistor if you want to be
sure they are matched.
73, Bill W6WRT
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