When we talk about how much energy costs in electrical circuits, two important things are voltage and current. They help us figure out how much energy we're using, which affects our electric bills.

1. Voltage (V): Think of this as the pressure that pushes electric charges through the circuit. It tells us how much energy each charge has. If the voltage is higher, it means more energy can move in the same amount of time.

2. Current (I): This shows how much electricity is flowing, and we measure it in amperes (A). It tells us how many charges are moving through the circuit. More current means more energy is being used, which can make your bills higher.

To find out how much energy we use, we have a simple formula:

$$\text{Power (P)} = \text{Voltage (V)} \times \text{Current (I)}$$

Once we know the power in watts, we can find out the energy used in kilowatt-hours (kWh) over a certain time. Then, we multiply this by the cost per kWh to get the total cost.

So, keeping track of both voltage and current can really help us save money on our energy bills!