How to use a multimeter to check for short circuit, open circuit, and leakage?
INDUSTRIAL LCD DISPLAYS / IGBT MODULES DISTRIBUTOR

Infineon / Mitsubishi / Fuji / Semikron / Eupec / IXYS

How to use a multimeter to check for short circuit, open circuit, and leakage?

Posted Date: 2024-01-24

How to use a multimeter to check for short circuit, open circuit, and leakage?

A multimeter is a very useful tool for detecting problems such as short circuits, opens, and leaks in electrical circuits. In this article, I'll detail how to use a multimeter to find these problems and provide some things to note during the inspection process.

1. Find short circuit problems:

A short circuit refers to an excessive current that occurs when current fails to flow along its intended path in a circuit. Here are the steps to use a multimeter to find a short circuit:

1. Cut off the power supply: Before starting the test, make sure the circuit is turned off, cut off the power supply and unplug the power plug to ensure your own safety.

2. Select the measurement mode: turn on the multimeter and turn the knob to the mode of measuring resistance (Ω).

3. Connect the multimeter: Connect the two test leads of the multimeter to the corresponding test terminals. One lead is connected to one node of the circuit and the other lead is connected to another node of the circuit. If a short circuit is found, the resistance value will appear to be almost zero or a very small value.

4. Step by step investigation: If the resistance value is found to be zero on a node, then this is a short circuit point. Disconnect the circuit and conduct a local inspection to determine the specific component causing the short circuit. This could be a collision between wires, a bare or soldered spot between two wires, or a short between two pins.

5. Repair the short circuit: Once you find the component causing the short circuit, repair the problem and reconnect the circuit. If the short cannot be repaired, you may need to replace the damaged component.

Precautions:

- When looking for a short circuit, make sure all circuits are turned off and the source of current is disconnected.

- Short circuits can sometimes be caused by charging of capacitors, so be sure to discharge the capacitor before testing.

- If using a digital multimeter, make sure the test range and accuracy are set correctly.

2. Find the circuit break problem:

A break is a break or interruption in an electrical circuit that prevents current from continuing to flow. Here are the steps to use a multimeter to find a broken circuit:

1. Cut off the power: As when looking for a short circuit problem, make sure the circuit is off, cut off the power and unplug the power plug.

2. Select the measurement mode: Turn the multimeter knob to the resistance measurement mode (Ω).

3. Connect the multimeter: Connect one test lead to one node in the circuit and place the other lead on another node in the circuit. If there is no break in the circuit, the multimeter will display a specific resistance value.

4. Step-by-step troubleshooting: If during the test, the resistance value displayed by the multimeter is infinite (OL) or a very large value, it means that there is an open circuit in the circuit. Determine the exact location causing the open circuit by examining each component in the circuit one by one. This could be something like a damaged wire, loose connector, or burned out component.

5. Repair the break: After finding the components causing the break, repair or replace them and reconnect the circuit.

Precautions:

- When looking for a break, also make sure all circuits are turned off and the source of current is disconnected.

- If there are capacitors in the circuit, be sure to discharge them before testing.

- If using a digital multimeter, make sure the test range and accuracy are set correctly.

3. Find leakage problems:

Leakage refers to the current in a circuit flowing to the ground or other paths without passing through the intended path. Here are the steps to use a multimeter to find leakage problems:

1. Cut off the power supply: Make sure the circuit is turned off, cut off the power supply and unplug the power plug.

2. Select the measurement mode: Turn the multimeter knob to the voltage measurement mode (V).

3. Connect the test leads to the circuit: Connect one test lead to a node in the circuit and the other lead to a safe ground, such as earth or ground.

4. Read the voltage value: Turn on the power and observe the voltage value displayed by the multimeter. If the voltage is found to be zero or very close to zero, it means no leakage is occurring in the circuit. If the current is large, then there is a leakage problem.

5. Step-by-step troubleshooting: Move the test lead from the safe ground point to other nodes in the circuit and continue to read the voltage value. If a large voltage value is found on a certain node, it means that there is a leakage problem at this node.

6. Repair leakage: After finding the components causing the leakage, repair or replace them and reconnect the circuit. If you find that the leakage problem is serious and cannot be repaired, it is best to call a professional electrician to deal with it.

Precautions:

- When looking for leaks, make sure to use your multimeter safely and follow all necessary safety regulations.

- When looking for leaks, care should be taken to avoid touching exposed wires or conductors to avoid the risk of electric shock.

Summarize:

Using a multimeter to find shorts, opens, and leaks in a circuit can help us locate and resolve circuit faults. However, you must ensure safety when operating, cut off the power supply and follow the correct steps. If you encounter a problem that cannot be solved, it is best to ask professionals, such as electricians, to help solve it.


#multimeter #check #short #circuit #open #circuit #leakage