#### Power circuit equation

## What is the formula for power in a circuit?

A circuit element dissipates or produces power according to P=IV, where I is the current through the element and V is the voltage across it. Since the current and the voltage both depend on time in an ac circuit, the instantaneous power p(t)=i(t)v(t) is also time dependent.

## What is Circuit formula?

R_{tot} = 8 Ω Now the Ohm’s law equation (ΔV = I • R) can be used to determine the total current in the circuit. In doing so, the total resistance and the total voltage (or battery voltage) will have to be used.

## What is the formula for power in watts?

The formula for calculating wattage is: W (joules per second) = V (joules per coulomb) x A (coulombs per second) where W is watts, V is volts, and A is amperes of current. In practical terms, wattage is the power produced or used per second.

## What is the efficiency formula?

Efficiency is often measured as the ratio of useful output to total input, which can be expressed with the mathematical formula r=P/C, where P is the amount of useful output (“product”) produced per the amount C (“cost”) of resources consumed.

## What is Ampere formula?

Since power is defined as the product of current and voltage, the ampere can alternatively be expressed in terms of the other units using the relationship I = P/V, and thus 1 A = 1 W/V. Current can be measured by a multimeter, a device that can measure electrical voltage, current, and resistance.

## What is the formula for current?

Current is usually denoted by the symbol I. Ohm’s law relates the current flowing through a conductor to the voltage V and resistance R; that is, V = IR. An alternative statement of Ohm’s law is I = V/R.

## How do you simplify a circuit?

Strategy for simplifying a resistor networkBegin as far away as possible from the circuit location in question.Replace series or parallel resistors with their equivalent resistor.Continue, moving left until a single equivalent resistor represents the entire resistor network.

## What is the power in a circuit?

Electrical Power, ( P ) in a circuit is the rate at which energy is absorbed or produced within a circuit. The quantity symbol for power is P and is the product of voltage multiplied by the current with the unit of measurement being the Watt ( W ).

## How do I calculate kVA?

Calculation with line to line voltageS_{(}_{kVA}_{)} = √3 × I_{(}_{A}_{)} × V_{L-L}_{(}_{V}_{)} / 1000.So kilovolt-amps are equal to √3 times amps times volts divided by 1000.kilovolt-amps = √3 × amps × volts / 1000.kVA = √3 × A ⋅ V / 1000.S = √3 × 12A × 190V / 1000 = 3.949kVA.

## What is kWh formula?

A kilowatt-hour, expressed as kWh or kW·h, is a measure of energy that is equivalent to 1,000 watts of power for a 1-hour time period. Thus, to convert watts to kilowatt-hours, multiply the power in watts by the number of hours, then divide by 1,000. For example: let’s find the kWh of 1,500 watts for 2.5 hours.

## How do you calculate total power?

The SI unit of power is the watt, where 1 watt = 1 joule per second. Back to our circuit! To use the power rule (P = I × V), we need to know both the current through the resistor, and the voltage across the resistor. First, we use Ohm’s law ( V = I × R ), to find the current through the resistor.

## What is thermal efficiency formula?

So, for a boiler that produces 210 kW (or 700,000 BTU/h) output for each 300 kW (or 1,000,000 BTU/h) heat-equivalent input, its thermal efficiency is 210/300 = 0.70, or 70%. This means that 30% of the energy is lost to the environment. An electric resistance heater has a thermal efficiency close to 100%.