Commercial circuit design utilizes electrical engineering. Circuit designers are constantly working to improve the speed and efficiency of circuits while also keeping cost of production down as much as possible. Circuit designers work across many different manufacturing fields. Nearly everything has a circuit in modern electronics; computers, microwaves, phones, refrigerators, televisions, headphones, even cars. Circuits are responsible for directing power; as a result, circuits are vital to the functionality of what they are a part of. Without circuits, appliances and other electronics would likely not be as complex as they are today.