Voltage Resistance Power

The power p in watts w is equal to the voltage v in volts v times the current i in amps a.

Voltage resistance power. More specifically ohm s law defined that the current i through a conductor between two points is directly proportional to the voltage v and is inversely proportional to the resistance r. 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. V v i a r ω. The voltage v in volts v is equal to the current i in amps a times the resistance r in ohms ω.

This calculator is based on simple ohm s law as we have already shared ohm s law p i v r calculator in which you can also calculate three phase current. Just like voltage resistance is a quantity relative between two points. V i r and the power law equation formula. So for this analogy remember.

The power used or dissipated by a resistor can be found using the formula v ir. The nominal impedance z 4 8 and 16 ohms loudspeakers is often assumed as resistance r. For this reason the quantities of voltage and resistance are often stated as being between or across two points in a circuit. In this calculator table you may enter two of the four factors in ohm s law.

Voltage is represented in equations and schematics by the letter v. For very low values of resistance for example milli ohms mω it is sometimes much easier to use the reciprocal of resistance 1 r rather than resistance r itself. For example in an open circuit condition voltage is present but there is no current flow i 0 zero therefore v 0 is 0 so the power dissipated within the circuit must also be 0 likewise if we have a short circuit condition current flow is present but there is no voltage v 0 therefore 0 i 0. V voltage electric potential difference δ v or e electromotive force emf voltage.

When describing voltage current and resistance a common analogy is a water tank. Power voltage current resistance p v i r calculator. The amount of current in a circuit depends on the amount of voltage and the amount of resistance in the circuit to oppose current flow. P power i or j latin.

Power within an electrical circuit is only present when both voltage and current are present. In this analogy charge is represented by the water amount voltage is represented by the water pressure and current is represented by the water flow. This formula can be used to substitute for the voltage or for the current in the power formula and the power output of a battery that has internal resistance can be found using the formula v ε ir and the formula for power. P i v.

Power in a resistance is always positive regardless of voltage polarity and current direction. But we have designed this one especially for dc circuits as well as work for single phase ac circuits without power factor.