Electronics - Ohms Law

Show/Hide:DefinitionsFormulae Instructions

Introduction:

This page allows you to input two out of the four values for a steady-state 'Ohm's Law' problem, and calculate the remaining values, regardless of which two values are provided.

Caveats:

If you are reading this paragraph, then you probably don't have JavaScript installed/enabled on your computer.
At this point in time the calculators on this site are entirely dependent on JavaScript. Given enough time and money it is hoped to develop a version in the future which will be able to operate independently. Since JavaScript runs on your own computer, rather than on this server, it has been possible to set up this site much more quickly than if a server-side language was used, and it is possible to serve far more pages with the available bandwidth.
If you think that you can assist with this project in any way, then please visit the Support section and leave a message.

Definitions:

Voltage v
The unit of electromotive force or electric pressure, the potential difference between two points in an electrical circuit, measured in Volts.
Current I
The rate of flow of electricity through a conductor, measured in Amperes.
Resistance R
In dc circuits, the opposition a material offers to current, measured in Ohms (Ω) In ac circuits, resistance is the real component of impedance, and may be higher than the value measured at dc.This page only contains formulae for steady-state (DC) circuits.
Power P
The rate of work done, measured in Watts (= joules/second)
DC
Direct Current. Compare with Alternating Current (AC)

• V = I * R
• P = I * V

Instructions

1. Fill in at least two boxes with the values that you know
2. Change the units for all 'input' fields, if required
3. Change the units for any output fields necessary
4. Click the 'CalcResult' button below the input fields
5. The value of the blank fields will be calculated
6. A 'Results Area' will be displayed below.
7. All known values will be shown. (Values for which insufficient information was given will also be identified.)
8. To do further calculations simply change any values in the input fields and click the 'CalcResult' button again. (Press the 'Clear Form' button if you want to empty all of the input fields.)
9. Press the 'Clear Results' button if you wish to discard the first results, otherwise further calculations will be added into the same area.
10. Click the 'CalcResult' button again
11. Click the 'Print Results' button to display all current results in a new, printable window.
D.C. Values