CommercialApprox

Simple Python Package that rounds arbitrary values to the nearest E-Series preferred values. Those values are commonly seen in commercial resistors and capacitors.

Disclaimer

This is only an approximation. The resistor and capacitors values highly depend on their availability at your local stores. The values are generated following the IEC 60063:2015 standard that not necessarily is practiced by all producers.

Usage

The package contains a single class that is responsible to generating the E-Series tables every run.

Here's an example code:

a = CommercialValueApproximator()

val = 11312

a.Approx(val) # -> Gives the best approximation 
a.Upper(val)  # -> Gives the best upper approximation
a.Lower(val)  # -> Gives the best lower approximation

In case there's the need to select even lower values based on a starting value, the Lower and Upper function can be chained to swipe the existing values.

For example, the following code:

print("Trying to step down value by multiple calls")
val = 1874
print(f"{val} -> ",end='')
for i in range(14):
    val = a.Lower(val) # <- multiple calls on the already approximated value
    print(f"{val} -> ",end='')
print(a.Lower(val))
print()

Will produce the output:

Trying to step down value by multiple calls
1843 -> 1800.0 -> 1500.0 -> 1200.0 -> 1000.0 -> 830.0000000000001 -> 680.0 -> 560.0 -> 459.99999999999994 -> 380.0 -> 320.0 -> 260.0 -> 220.00000000000003 -> 180.0 -> 150.0 -> 120.0 

This method wont work when using the Approx method.