Power Dissipation Calculator

Power dissipation is the process by which electrical energy is converted to heat in a resistive component. When current flows through a resistor, the electrical energy is lost as heat, and this lost energy is called power dissipation.

There are three main formulas: P = VI (power equals voltage times current), P = V²/R (power equals voltage squared divided by resistance), and P = I²R (power equals current squared times resistance). Use the formula based on which values you know.

In a series circuit, calculate the total resistance by adding all resistor values. Find the current using Ohm's law (I = V/R total), then calculate power for each resistor using P = I²R, where I is the same for all resistors.

In a parallel circuit, voltage is the same across all resistors. Calculate power for each resistor using P = V²/R, where V is the source voltage and R is each individual resistor value.

In a series circuit, the resistor with the highest resistance dissipates the most power, since current is constant and P = I²R. The power dissipation is directly proportional to the resistance value.

Heat dissipation equals power dissipation in resistive circuits. The power calculated (in watts) directly represents the rate of heat generation. To find total heat energy, multiply power by time (P × t = energy in joules).

You need at least two parameters to solve for the third. If you know voltage and power, you can find current (I = P/V) or resistance (R = V²/P). The calculator will automatically compute missing values when possible.

For the same resistors and voltage source, parallel circuits dissipate more total power than series circuits. This is because parallel circuits have lower total resistance, allowing more current to flow and resulting in higher power consumption.