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Calculating standard resistor values



FYI...  I find these equations very handy in selecting resistor values...

These Excel equation will calculate standard E24-5%, E48-2% and E96-1% standard resistor values..

Paste into a cell, change the three references from A1 in the equations below to the cell with the required values, and it will give you the new closest standard value...
( It can be expanded to E192-0.1% by changing the five references of "96" to 192, but, I avoid using 0.1% values)

This will give you error in %, from old value (A1) to new value (A2)
=ABS(((A1-A2)/A2)*100)

For E96
=ROUND((10^(ROUND(96*LOG(A1),0)/96))/10^INT(LOG((10^(ROUND(96*LOG(A1),0)/96)))),2)*10^INT(LOG((10^(ROUND(96*LOG(A1),0)/96))))

For E48
=ROUND((10^(ROUND(48*LOG(A1),0)/48))/10^INT(LOG((10^(ROUND(48*LOG(A1),0)/48)))),2)*10^INT(LOG((10^(ROUND(48*LOG(A1),0)/48))))

For E24
=ROUND((10^(ROUND(24*LOG(A1),0)/24))/10^INT(LOG((10^(ROUND(24*LOG(A1),0)/24)))),1)*10^INT(LOG((10^(ROUND(24*LOG(A1),0)/24))))



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Tom Lafleur