When you are trying to solve a problem in your house, it can be difficult to know what is wrong. You may think that there is something wrong with the circuit breaker because the lights go out when you turn on an appliance. However, before you start ripping apart your walls, read this article to find out what the difference between an open circuit and closed circuit is!
The Open Circuit Definition
An open circuit is an electrical or electronic circuit with no complete route for the electric current to flow from the source to the load or back.
An open circuit can be created deliberately, for example by breaking a wire in two, or it can happen accidentally, as when a switch is opened or a short-circuit occurs.
In electronics and electrical engineering, an open circuit may also refer to a discontinuity in an otherwise linear network, resulting in infinite impedance. This causes all energy flowing through the network to dissipate as heat at the open circuit node.
In my view, this explanation of an open circuit is concise and informative. It defines an open circuit as a path where electric current can’t flow, whether intentionally or accidentally. It also mentions the concept of infinite impedance and the use of open circuits to create switches for power control. It’s a clear and practical explanation of open circuits.
James Johnson, Electronics Technician, San Francisco
Open circuits are often used to create switches, which can turn power on and off without having to break the circuit completely.
An open circuit has one or more faulty pathways for electricity current to flow through. Even if a power supply has at least one broken route, it is still referred to as an open circuit [1].
Without a complete pathway for electricity to flow through the circuit, it is not possible for any load connected to this circuit to receive power from the source. In other words, if a device or appliance is powered by an open-circuit, then that device will stop working immediately.
Hence, as long as there are broken paths of electric current inside an open-circuit, electrons cannot move towards the positive terminal of battery because they have nowhere to go.
Features:
- When a circuit is open, current does not flow through it. This means there are no completed closed pathways for the electricity to pass from one place to another. This also implies that when an electric charge passes through an “open” circuit, nothing happens and this can therefore be referred to as a dead short or “no path at all”. In other words, there will be zero voltage across the load terminals in such cases since they have no way of connecting with each other (to complete the loop) and hence cannot produce any potential difference between them;
- An open circuit does not allow any load to be connected to it since there are no completed paths for the electric current from the voltage source to flow through. This implies that an “open” circuit can never complete a closed-loop between its two terminals, which means that the system becomes unstable and hence incapable of producing energy or power. In other words, it is impossible for this type of electrical/electronic circuit to work alone;
Applications
Open circuits are useful in electronics and electrical engineering where they can sometimes be used to test the integrity of a circuit. It is also possible for them to act as an intentional interruption in current flow, which might occur when certain switches or relays are activated. This can be used to create small circuits or even full-sized ones.
For example, when a switch is opened, it creates an open circuit so that no current flows through the lightbulb.
An open-circuit can also be created accidentally as a result of a short-circuit. If there is a sudden increase in current flow (due to, for instance, a metal object coming into contact with live wires), this can cause the electrons to flow too quickly for the gaps between atoms to close properly.
In the field of electronics, open circuits are usually created purposely to check whether or not a circuit is complete. This can be done using what is known as an ohmmeter, which performs this test by measuring the resistance and conductance in different points along any given path. Open circuits might also occur accidentally when there has been a problem with electrical wiring.
The Closed Circuit Definition
It is defined as any electrical or electronic circuit that has a whole path for the flow of electric current. Experts may describe a circuit with no broken paths as being closed-circuit, or we might say it’s a closed circuit if there are no breaks in the route for electricity to travel from source to load and back. Current can flow from source to load and return on an open-circuit gearbox [2].
A closed circuit will also provide a complete path for the electric current, meaning that electrons can flow smoothly from one end to the other. This allows for voltage and power to be produced across the load terminals as long as it is connected in the right way.
Robert Wilson, PCB Designer, New York
It should be noted that a closed circuit does not have to include any components like resistors or capacitors – these are only used in order to control and modify the behavior of current within a given system.
Features:
- A closed circuit has no open pathways where electric current can escape, meaning that it provides a complete path for electricity to flow. In other words, the voltage will be present across the terminals of any load connected to it (provided of course that there’s enough power supply) since they are now able to connect with each other and create a completed loop;
- As opposed to an open circuit, a closed one allows for the load to be connected and hence can provide power;
- Closed circuits are much more stable and reliable than open ones, as they do not have any broken or interrupted pathways that could lead to malfunctions. This is why closed circuits are often used in electrical appliances and machines where reliability is key;
Applications
Closed circuits are found in a wide range of everyday devices, from simple light bulbs to more complex machines like cars and airplanes. In fact, many electronic gadgets would not work without closed circuits, as these provide the stable foundation for current to flow and enable different components to function properly.
Some common applications of closed circuits include:
- Lighting systems;
- Electric motors;
- Heating appliances;
- Air conditioning units;
- Refrigerators;
It is important to note that any device that contains a microchip will also require a closed circuit for it to function correctly. This is because microchips need a steady stream of electricity in order to operate. As such, if the circuit supplying power to the chip is interrupted or malfunctions.
An example of a simple electrical circuit that uses the principles underlying open and closed circuits is the light switch in your home. The purpose of this device is to provide you with an easy way of turning lights on and off, which it does by interrupting or closing (closing) the electric current flowing through itself so as to create either an “on” or “off” state for any given appliance.
In other words, when you press down on a button connected between two poles inside a wall socket belonging to your house, you are actually activating what we call a mechanical-electrical component whose job is to close the pathway for electricity flow: hence creating a closed circuit. In this way, the switch controls the power flow between a voltage source and an appliance connected to it.
It consists of two electrodes (anodes and cathodes) placed very close together inside a glass bulb filled with electrolyte fluid. When electricity flows from one electrode to another through such fluids, free electrons are created at their interface due to what we call ionization or oxidation reactions.
These ions move by diffusion towards the other electrode where they combine with positive charges in order to neutralize themselves: hence completing a circuit that can be used for many applications including converting DC into AC current, rectifying alternating currents, protecting against over-voltages and over-currents, and detecting small current signals.
Closed circuits find extensive use in all types of electronic devices and equipment. They are a fundamental component of most gadgets and machines as they help ensure a stable flow of electric current without interruption. In fact, almost every appliance you see around your house makes use of closed circuits somewhere within its circuitry. From televisions to air conditioners, from refrigerators to microwaves – they all employ closed circuits to achieve their intended functions.
Difference between Open Circuit and Closed Circuit
1. The significant distinction between an open circuit and a closed circuit is that in a closed circuit, there is no damaged pathway, whereas the open circuit has at least one broken path.
An open circuit is a damage in the pathway of current flow. There are two possible reasons for an open circuit – either there is a damaged cable or it is not connected at all. A closed circuit, on the other hand, has no broken path and can be traced to its origin point if required. Another key difference between both circuits lies in their functionality:
In an open circuit, when electrical charges move through the wire they do so only up until that particular spot with the breakage; beyond this area, there will be nothing happening (no charge movement). In contrast to this behavior of currents moving around undoubtedly until they hit something obstructing them out of their course (like solid objects), closed circuits don’t allow any current flow except through the closed loops.
2. In an open circuit, the current flows from the power source to the load, but because of the break in the wire, it doesn’t flow back to the power source. In a closed circuit, the current flows in a circle and goes back to the power source.
3. In an open circuit, electrical energy does not flow; however, energy can be transferred from the source to the load via a closed circuit.
Daniel Smith, Embedded Systems Engineer, Los Angeles
Check more posts to improve your experience in electronics:
- Normally Open vs. Normally Closed
- How to Build a Prototype Electronic Circuit?
- What is Star Delta Starter Circuit?
FAQ
1. What is meant by open circuit?
An open circuit is a circuit with an interruption or “opening” in it somewhere so that the current will not flow.
An open circuit, also known as an incomplete circuit, is one in which the path has been cut off. To say that the circuit breaker or fuse “opened” or tripped the system is a typical electrical industry phrase [3].
2. What is closed circuit in physics?
A closed circuit is an electrical circuit in which the current flows around a complete path. The electrons flow continuously around the loop, never leaving the conductor. A closed circuit allows electricity to flow freely and this creates a steady stream of energy.
In your home, you likely have a light switch that uses the principles of open and closed circuits. When you press down on the button connected between two poles inside a wall socket, you are actually activating what we call a mechanical-electrical component – known as a switch – whose job is to close (close) the pathway for electricity flow: hence creating a closed circuit.
This will allow power to flow from a voltage source (i.e. your house’s electrical grid) and light up the bulb. The moment you release the button, it will open (open) the circuit again and break the connection between the poles, stopping power from flowing to the lightbulb.
3. What is an open circuit example?
An open circuit is a type of electrical circuit where there is no complete current. This means that the circuit is not completed, and electricity cannot flow through it.
An example would be when you have two wires connected to each other but without any equipment attached between them; this leaves an open path for electrons from one wire to another because they are disconnected by air or some kind of insulator like plastic or rubber instead of connecting into something such as a light bulb.
In electronics, if your battery has lost its charge then it will also leave behind an “open” connection in which energy cannot get transferred properly across the device’s components even though power might still be on (and sometimes can damage key parts).
4. What causes an open circuit?
An open circuit can be caused by a number of things. One common reason is that there’s a break in the wiring, such as when a wire has been severed.
Another possibility is that a component like a fuse has blown and no longer allows current to flow through the circuit.
Finally, you might also have an open circuit if there’s something blocking the electrons from traveling along the path they’re supposed to take, such as air or insulation material.
5. What is the potential difference in an open circuit?
There is a drop in potential difference (p.d.) across the cell’s internal resistance. As a result, the p.d. across the terminals of a closed circuit is lower than that of an open circuit by an amount equal to the potential drop across the cell’s internal resistance [4].
6. Does an open circuit have voltage?
When a load is connected and the circuit is closed, the source voltage is divided across it. When the full-load of a device or circuit is disconnected and the circuit is opened. However, the open-circuit voltage equals the source voltage [5].
7. Why does electricity not flow in an open circuit?
In an open circuit, the current is not able to flow because the path has been interrupted by some kind of insulator that breaks down the connection between different points.
The reason why electrons do not flow through empty space (in the air) is due to electric fields. While there are no opposing charges present within a vacuum, it does have many charged particles present and you can think of these as being like magnets with positive and negative ends which repel each other if brought too close together:
When one object attracts another then we say that one object has more “pull” than another – this means that their forces on each other will be stronger than those that would exist between two objects where neither pulls harder or against the other.
So in the case of an open circuit, you have two objects (electrons and the positive end of a battery for example) that are trying to move towards each other, but because there’s nothing stopping them from doing so they will just keep moving further and further away from each other. This is what creates an open circuit: without anything to stop or slow down the electrons, they simply flow around whatever obstacle might be in their way.
Useful Video: Open Circuits, Closed Circuits & Short Circuits – Basic Introduction
References:
- https://www.etechnog.com/2021/07/open-circuit-closed-circuit.html
- https://www.etechnog.com/2021/07/open-circuit-closed-circuit.html
- https://c03.apogee.net/mvc/home/hes/land/el?utilityname=citizenselectric&spc=foe&id=4702
- https://www.topperlearning.com/answer/explain-why-the-pd-across-the-terminals-of-a-cell-is-more-in-an-open-circuit-and-reduced-in-a-closed-circuit/8f6gjjqnn
- https://www.electrical4u.com/open-circuit-voltage
