To use this page,
Ensure the list of resistors is correct for your collection.
You can populate the list with one of the buttons but any custom values added will be lost.
The list of resistors will be automatically saved on exit and restored when next used.
Once the resistor values are correct, enter the desired (parallel) value in the third column and press calculate to get a list of available combinations.
A list of values will then be displayed.
R1 and R2 are the two resistors to be paralleled.
Go on, guess what the other columns are!!
It is assumed that only 1 decade of values is required (seems that was wrong so added the ability to use more decades)
and anyone needing (for example) a 250Ω resistor will enter 25
as the desired value and use ten times the values for R1 and R2 (360 and 820).
Should there be a need to include other decades then the code could be has been modified to do so.
Likewise, if it's thought necessary to add E48 values etc. then they can also be added.
For some reason JavaScript doesn't like fractional values so if you require a small parallel value then use larger values and scale appropriatly.
Ohm's Law is named after German Physicist Georg Ohm when he discovered the relationship in 1827.
It states that the current through a conductor between two points is directly proportional to the voltage across the two points.
As diferent materials conduct differently, it's not always the same. Ohm came up with a name for this reluctance to carry current - resistance.
Resistance is therefore measured in Ohms and uses the Greek symbol Omega (Ω) to represent it.
Link to wiki page.
The above image is a visual reminder of the rule with the three possible equations.
I remember the V=IR version and for any of the others I simply move the I or the R under the V to get the other two equations.
To use the above calculator, insert any two of the parameters and press calculate then the third (blank) one will be worked out.