Ohms Law Power

The combination of ohm s law and joule s law gives us 12 formulas where 2 of the 4 variables are known.

Ohms law power. Ohm s law states that the current through a conductor between two points is directly proportional to the voltage across the two points. P is for power measured in watts i is for current and the e is for voltage. Where i is the current through the conductor in units of amperes v is the voltage measured across the conductor in. Simple to use ohm s law calculator.

Ohms law pie chart. V v i a r ω. Ohms law pie. Learn the power formula.

How to use ohm s law to determine current. P v x i. We ve seen the formula for determining the power in an electric circuit. In ohms law we know that i e r so combined with the power equation p ie we get p e e r or p e 2 r.

Introducing the constant of proportionality the resistance one arrives at the usual mathematical equation that describes this relationship. Calculate power current voltage or resistance. The problem is determine the resistance r and the voltage source v sub s. To help us understand the the relationship between the various values a little further we can take all of the ohm s law equations from above for finding voltage current resistance and of course power and condense them into a simple ohms law pie chart for use in ac and dc circuits and calculations as shown.

In the above circuit we know we have a battery voltage of 18 volts and a lamp resistance of 3 ω. The topic of this problem is ohm s law and also using the well known equation for power as well. They are power p or w measured in watts voltage v or e measured in volts current or amperage i measured in amps amperes and resistance r measured in ohms. Ohm s law calculations with power in the four tables below you may enter two of the four factors in ohm s law.

By multiplying the voltage in volts by the current in amps we arrive at an answer in watts let s apply this to a circuit example. Power is typically produced by electric generators and supplied to businesses and homes through the electric power industry but can also be supplied by electric batteries or other sources. P is power measured in watts. In resistive circuits joule s law can be combined with ohm s law to produce alternative expressions for the amount of power dissipated as shown below.

Just enter 2 known values and the calculator will solve for the others. The power p in watts w is equal to the voltage v in volts v times the current i in amps a. The voltage v in volts v is equal to the current i in amps a times the resistance r in ohms ω. This equation can be combined with ohm s law to solve for values that are unknown.

And that s the v sub s that we re looking for. The wheel below is a handy tool and memory jogger.