What is a short circuit? (Beginners, 2024)

Apart from open and closed circuits, a short circuit is also a term used in electronic circuits.

Opposite the open circuit, there is a short circuit. Technically speaking, any two electrical points on a board or circuit that offer zero resistance are called short circuits. Incorrect wiring, damaged components, soldering mistakes, excessive heat, and damaged insulation can result in short circuits.

In this article, We will examine the short circuits, including their causes, effects, detection, and prevention.

Table of Contents

Short circuit

In the circuit, there is a dedicated path for current flow which is from source to load.

The short circuit occurs when the current starts flowing through the path that has less resistance and is shorter than the dedicated path.

When electrical current flows in a way that could harm the circuit, it is called a short circuit. Using an example we’ll explain more about a short circuit. Let’s consider a circuit powering a light bulb with a battery.

When you connect the positive terminal of a battery to the negative terminal of a battery it means you have created a short circuit.

In the short circuit, the current doesn’t follow the intended path and the path it follows doesn’t have the load to use this electricity.

Without load the current is uncontrol and a short circuit will heat the wires from the flow of current to the point where the insulation melts, catches fire, or even melts the copper wire itself.

The battery also heats up and it may explode and can also damage the component, in this case, due to a short circuit the bulb with be damaged.

As the current follows a shorter path that’s why it is called a short circuit. In a short circuit, the resistance is zero.

From the above circuit, you can see that it is short because the current has to be passed through the bulb but all the current is passing through the point A and B. Now applying Ohm’s law

V_AB=IR

The voltage between points A and B is given by

V_AB=V_A-V_B

V_AB=0

R=V_AB/I

R=0

The resistance becomes zero in the short circuit and a very high current flow in the circuit which can damage the circuit and the components.

The following are basic things you should keep in mind about a short circuit.

The voltage difference across a short circuit is always zero
Any amount of current can flow into a short circuit. And this is the reason we often hear a building catch fire because of an electrical short circuit.

we combine two components by connecting their terminal, this is good and this is how we connect components. But if we short the connection of the two terminals of the same device we might end up damaging that device.

Causes of short circuit

Several reasons can cause short circuits when working with electronic circuits. The following is a list of potential short circuit reasons.

1. Incorrect wiring

Incorrect wiring is the common cause of short circuits. When don’t connect the components according to the circuit diagram it will lead to the low resistance path and this causes the short circuit.

This can happen due to multiple reasons such as connecting the wrong components, reversing the polarity of power, or neglecting proper orientation.

Consider a circuit with different components like resistors, capacitors, and transistors. Each component has a defined role and should be connected in a particular way.

These incorrect wiring situations cause a short circuit and provide a path to the current other than the intended path.

Make sure you connect components and power sources according to the circuit diagram.

2. Soldering mistakes

The soldering mistakes can also lead to short circuits. It will cause an unexpected connection and will create a new path for the current to flow.

One of the common issues is solder bridges, where molten solder unintentionally connects adjacent conductive elements.

This occurs when excess solder is applied and two closed components get connected this way a low-resistance path is created and disturbs the normal flow of current.

Poor soldering techniques like cold solder joints and applying insufficient solder, can result in unreliable connections, introducing resistance and potential points of failure.

Proper soldering techniques are essential for secure and insulated connections between the components.

3. Damaged components

When a component is damaged, its structural integrity becomes compromised, creating unexpected paths for electrical current that might cause short circuits in a circuit.

Several things, including wear and tear, defects in manufacturing, and external stressors, can cause this damage.

For example, An externally cracked or broken resistor or capacitor may reveal the conducting material inside.

In this situation, a short circuit might result from the exposed conductive elements coming into touch with adjacent conductors or components, which opens up a low-resistance path for current to flow.

When you are connecting various components make sure you check the components and that they are all well-insulated and in good condition.

4. Excessive heat

When temperatures rise above what is considered safe for electrical components, several negative consequences could arise.

The degradation or melting of insulating layers around conductive components, including wires and traces on circuit boards, is one frequent result.

Heat-induced insulation breakdown can bring nearby conductors into direct contact, resulting in an unintentional electrical route and a short circuit.

Using components with sufficient power ratings is crucial to preventing short circuits caused by overheating.

5. Loose wires or connections

Another reason that can cause a short circuit is a loose wire or connection between the components.

When a wire is not perfectly fastened it may get connected to another wire, which can lead to an unintentional connection between the conductive elements.

This unintentional connection is problematic because it can cause unexpected pathways for current to flow and will result in a short circuit.

To prevent short circuits caused by loose connections, it is essential to ensure that all wires and connectors are securely fastened during the assembly process.

6. Damage insulation

The insulation surrounding wires and conductors serves a crucial role in preventing unintended contact and maintaining the integrity of the circuit.

When the insulation is damaged, either due to wear and tear, physical stress, or environmental factors.

This allows the conductor to directly come in contact with other conductive materials, creating a low-resistance pathway for electrical current to flow.

Consequently, the current takes a shortcut rather than following the set path across the circuit, resulting in a current surge.

Regular inspection and proper handling of wire are essential for preventing short-circuiting.

Conclusion

Grasping the concept of short circuits is a fundamental step for understanding the basics of electronics.

Besides closed and open circuits, a short circuit is also a term used in electronic circuits.

The short circuit represents a situation in which the current starts flowing through the short path and can damage the circuit. For a circuit to work properly means to provide current to the load, the current should pass through the load.

However, in the event of a circuit short, the current that needs to be transferred through the load starts flowing through the low-resistance path; in this scenario, an extremely high current may start flowing, endangering the circuit and its components.

Incorrect wiring, soldering mistakes, excessive heat, damaged components, loose connections, and damaged insulation are some reasons that might cause short circuits.

This was all about short circuits.

Thank you and stay blessed…