Electrical Circuits: The Bridge between Man and the Electric World

 

 System of a Circuit  (What is it?)

A circuit is a closed loop that enables electrons to travel throughout producing electrical energy. A source of electricity, such as a battery, provides electrical energy in the circuit. In order to allow the electrons to travel throughout the circuit, the circuit has to complete a full circle back to the electrical source. Generally, there is some appliance that uses electricity in the circuit. The appliance may, for example,  provide light or heat or mechanical energy. An electric circuit can be used to transport electrical power to provide electric lighting, to run electric motors, to recharge storage batteries, to provide heat for heating, for cooking, for melting metals, to monitor conditions such as in alarm systems, to store data to run diagnostic medical equipment, to run electric cars, trolleys and machines.

 

The parts of a Circuit 

A circuit has four primary parts: an energy source (AC or DC), a conductor (wire), an electrical load (device), and at least one controller (switch). The purpose of an energy source in a circuit is to produce an electric current from a source such as a battery into the correct voltage, current, and frequency to power the appliance. An alternating current (AC) is a type of  electrical current that changes periodically resulting in the electrons flowing in different directions at regular intervals and cycles. A direct current (DC) is the second type of electrical current in which the electrons flow throughout the current in only one direction.  AC often powers large appliances and motors and is generated by power stations, while DC powers battery operated vehicles and other machines and electronic. A conductor is made from a material that is conductive to the substance you are trying to power and takes on the role of carrying an electric current, which is where the electrons are flowing. Without a conductor, electrons would not be able to flow into your appliance, and energy would not be produced. Some examples of conductors include a wire, cable, or any other form of metal. An electrical load is a crucial component in producing energy and allowing the circuit to function properly. It’s part of a circuit that absorbs the energy produced, not to get confused with the energy source that is releasing the energy. Lastly, the final part of a circuit is the switch. The function of the switch is to open or close the circuit, by limiting or allowing the flow of electrons throughout the circuit. 

 

How does an electrical circuit work?

An electric circuit works by providing a closed loop to allow current to flow through a system. Electrons must be able to flow throughout the circuit, completing a path from one pole of the power source to the other. Electrons enter an electrical circuit through the source of the circuit. The point where the electrons leave an electrical circuit is often called the return or “earth ground”. It’s called the “return” because this is the point where the electrons always end up at the source when they complete one full cycle.The part of an electrical circuit in between the electrons’ starting point, the source and their ending point, the return is called the load. Along the way, this flow of electrons can be used to power lights or other electrical devices.

 

Series Circuits

There are two types of basic electrical circuits, the series circuit and the parallel circuit. In a series circuit, there is only one path for electricity to travel from the starting point to the ending point. The amount of electricity that is flowing through the current remains constant throughout the circuit. The rate in which the electrons are flowing throughout the circuit will never fluctuate. This means that not only is the amount of electricity, but also the speed in which electricity is flowing is constant as well. Most circuits also include resistors, which serve the purpose of reducing current flow,  varying signal levels, and dividing voltages. It regulates the flow of the current into other components of the circuit. The more resistors present in a series circuit, the more difficult it becomes for electrons to flow. Lastly, in a series circuit, the voltage is positive when entering the resistor, but converts to negative where it exits, while the polarity of the voltage across the battery is opposite to the voltage across the resistors.

Parallel Circuits

The second type of electrical circuit is the parallel circuit. In a parallel circuit, there are multiple paths for electricity to travel. In addition, the components present in a circuit are all connected by the same electrical common points. For example, in a parallel circuit, resistors and power sources are connected by two electrical common points. Also, in a parallel circuit, electrons are able to flow both horizontally and vertically in different directions simultaneously. Lastly, the components present in a circuit maintain same voltages and identical properties throughout the circuit. 

 

Sources

Power System. (n.d.). Retrieved from http://www.qrg.northwestern.edu/projects/vss/docs/power/2-whats-a-circuit.html.

How Electrical Circuits Work: Lighting Basics. (n.d.). Retrieved from https://www.bulbs.com/learning/circuit.aspx.

King, D. (2019, March 2). What Are Two Types of Electrical Circuits? Retrieved from https://sciencing.com/two-types-electrical-circuits-8246628.html.