|
Post by Happyguy on Feb 12, 2009 21:28:35 GMT -5
|
|
|
Post by newey on Feb 12, 2009 21:55:05 GMT -5
Thanks, HG-
I added this to our links page, under "Calculators and other Tools"
|
|
|
Post by ChrisK on Feb 12, 2009 23:50:20 GMT -5
Interesting summary of resistors. They have most of it right,
The statement is incorrect.
The E24 range is a subset of the E48 range, which is a subset of the E96 range. The numbers don't match since the E24 ones are rounded to two digits.
The "E", or exponent, numbers are the number of steps per decade of values. For a 1% resistor, there are 96 values derived from the 96th root of 10, for constant ratio spans thru each decade.
E Span Ratio Multiplier 6 1.467799 or */ 1.211527, the "20"% resistor 12 1.211527 or */ 1.100694, the 10% resistor 24 1.100694 or */ 1.049139, the "5"% resistor 48 1.049139 or */ 1.024275, the 2% resistor 96 1.024275 or */ 1.012064, the 1% resistor 192 1.012064 or */ 1.006014, the "0.5"% resistor
In fact, the tolerances themselves are rounded to convenient values.
|
|
|
Post by JohnH on Feb 13, 2009 18:39:38 GMT -5
That is a useful link indeed. To be quite honest, I never found out how to read the 5-band system for low tolerance resistors, until reading this.
John
|
|
|
Post by ChrisK on Feb 13, 2009 20:40:43 GMT -5
AND....the reliability rate proves beyond any shadow of doubt that only fools run resistors at or near their rated wattage.
Over a 30 career as an OEM electronics design engineer, I've never designed anything that uses one at over 50% of the rated wattage.
|
|