32 lines
1.7 KiB
Markdown
32 lines
1.7 KiB
Markdown
E-series defined in IEC 60063 are a widely accepted system of preferred
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numbers for electronic components. Available values are approximately
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equally spaced in a logarithmic scale. Although E-series are used for
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Zener diodes, inductors and other components, this calculator is mainly
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intended for resistors.
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E12: 1,0 1,2 1,5 1,8 2,2 2,7 3,3 3,9 4,7 5,6 6,8 8,2
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E6: 1,0 - 1,5 - 2,2 - 3,3 - 4,7 - 6,8 -
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E3: 1,0 - - - 2,2 - - - 4,7 - - -
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E1: 1,0 - - - - - - - - - - -
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If your design requires any resistor value which is not readily available,
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this calculator will find a combination of standard E-series components to
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create it. You can enter the required resistance from 0,0025 to 4000 KOhm.
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Solutions using 3 or 4 resistors are given if a better match can be found.
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The 4R checkbox option will take longer to process is considered for the E12
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series only. Optionally it is possible to exclude up to two additional
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values from the solution for the reason of being not available. If a
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E-series value is entered to the required input field, it is always excluded
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from any solution as it is assumed that this value is unavailable.
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Solutions are given in the following formats:
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R1 + R2 +...+ Rn resistors in series
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R1 | R2 |...| Rn resistors in parallel
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R1 + (R2|R3)... any combination of the above
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__Example:__ Voltage dividers, commonly used for 1:10 range selection
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require resistor ratio values 1:9. Unfortunately the "9" is a value, what
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is not even in the E192 series available. Deviation of 1% and more is yet
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unacceptable for 8 bit accuracy. For a required resistor value of 9 KOhm,
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the calculator suggests the E6 values 2k2 + 6k8 in series as a possible
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exact solution.
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