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Rojony Khatun Author
Rojony Khatun
CalculatorToolsProjectExpert
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Małgorzata Koperska, MD Steven Wooding
Last updated: September 23, 2025

Short Circuit Protection Circuit Using Relay for Electronics

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Mini Push Button Switch

Mini Push Button Switch

A simple mechanical switch used to make or break a circuit when pressed. It returns to its original position once released. Commonly used in doorbells, calculators, reset buttons, and control panels.

1K Fixed Resistor 1/4W

1K Fixed Resistor 1/4W

A 1,000-ohm resistor rated for 0.25 watts

3V LED 5mm

3V LED 5mm

3V, 5mm round light-emitting diode

5-pin Relay 12V DC

5-pin Relay 12V DC

Electromechanical relay with 5 pins, operates on 12V DC

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Short circuit protection using Relay

Protect electronic circuits from short circuits using a relay-based protection system. Automatically disconnects the load when overcurrent is detected, ensuring safety.

Relay safety switch electronics

The short circuit protection, with the help of a relay, automatically breaks the load when overcurrent is detected. Its relay is designed to open and close its contacts to avoid any damage to electronics, therefore, ensuring safety and reliability.

short circuit relay protection

Short Circuit Protection using a Relay is a mechanism that protects electronics. It encourages automatic disconnection of the load during a short circuit or overcurrent. A relay is a type of electrically operated switch, which may be used to interrupt the flow of current when a sensing device (a fuse, a current sensor, or a comparator, etc.) senses excessive amounts of current. The project is best suited to those hobbyists, students, and electronics enthusiasts who wish to shield DC circuits, small power supplies, or home-built devices. As soon as the current rises above a preset value, the sensing circuit makes the relay coil open the contacts and breaks power flow to the load. The circuit is automatically or manually reset following the clearing of the fault. A relay is a good and cost-efficient solution since it can be used to guarantee that high-current handling and low-voltage sensing circuits are separated. Safety is also achieved by proper testing and fuse integration.

Work / Installation (Inputs → Outputs)

  • Power Supply → Provides voltage to load and sensing circuit.
  • Current Sensing → Detects overcurrent using shunt resistor, fuse, or comparator.
  • Relay Coil → Energized or de-energized to open or close contacts.
  • Load Circuit → Receives power normally; cut off during short circuit.
  • Installation → Connect sensing circuit to relay coil, wire load through relay contacts. Test by simulating overcurrent; relay should trip and disconnect load.

Testing & Final Adjustments

Once it is assembled, put normal voltage on it and check to ensure that the load works as intended. To test for a short or overcurrent, the relay must open instantly, breaking the load. Tune current sensing devices to make the relay switch at the required level. Confirm that the relay contacts are free of arcing. Manually or automatically reset the circuit to recover adequately after a fault. Test various conditions to make sure that it works and is kept safe. Fit the parts correctly, and your electronics will be safe against unintentional shorts, making it a cost-effective and simple method of DIY, hobby circuit breakers, and so on.

Frequently Asked Questions - Short circuit protection using Relay:

What is a relay?

A relay is an electrically operated switch used to control high-current circuits.

How does it protect circuits?

It disconnects the load when overcurrent or short circuit is detected.

Can it handle high current?

Yes, relay contacts can be selected based on load current rating.

Is it beginner-friendly?

Yes, simple wiring with sensing and relay components.

Voltage requirement?

Depends on relay coil and load voltage.

Applications?

Hobby electronics, DIY projects, low-voltage power supplies.

Do I need a fuse?

Recommended to enhance protection and trip relay in overcurrent.

Can it reset automatically?

Yes, with suitable sensing circuit design.

How to test?

Simulate short circuit; relay should disconnect load.

Is it safe?

Yes, ensures load is disconnected before damage occurs.

Rojony Khatun

Rojony Khatun

CalculatorToolsProject

Rojony Khatun is the creator of a free online tools website designed to simplify everyday and engineering-related calculations for students, professionals, and hobbyists. The platform offers a wide variety of basic and advanced calculators across key categories, including Electrical Calculators, Electronic Calculators, and Time & Date Calculators, helping users solve problems quickly and accurately.