Electric Circuits: Electrical Energy

Energy Transfer in Electrical Circuits

Electrical energy transfers are a crucial part of understanding electric circuits.
The energy transferred (E) from electrical energy to other forms in a circuit can be calculated using E = VIt, where V is the voltage (or potential difference), I is the current, and t is time in seconds.
If resistance (R) and time are known, energy transferred can also be calculated using E = I²Rt.
Similarly, if voltage and time are known, the equation E = V²t/R can be utilised.

Energy and Power Dissipation in Electrical Circuits

Power dissipation refers to a circuit’s energy conversation in a given time. It is expressed in watts (W), where 1 W = 1 J/s.
The power (P) in an electrical circuit can be calculated as P = VI. In the equation, V is potential difference and I is the current.
Additional ways to measure power are with the formulas P = I²R and P = V²/R, depending on what information is at hand.
Power dissipation in resistive components like resistors is often released as heat. This is why resistors and other electronic devices warm up when used.

Conservation of Energy in Electrical Circuits

The principle of Conservation of Energy states that energy cannot be created or destroyed, only transferred or transformed.
In electrical circuits, voltage represents energy per unit charge. The battery or power supply gives energy to the electrons and this energy is transferred to other components in the circuit (e.g., bulbs) which dissipate energy (often as light and heat).
The sum of the electrical energy supplied to the circuit by the source (battery or power supply) is equal to the sum of energies dissipated in all resistive components.
Consider and apply this principle to problem solving - tracking the energy inputs, transfers, and transformations enables you to check your solutions for consistency with Conservation of Energy.

Understanding these principles, applying the correct formulas and appreciating how electrical energy is transferred and dissipated in a circuit will be beneficial in handling questions around electrical energy in electric circuits. Happy revision!