Blown multimeter fuse (guide, why and how to fix it)
Content
The DMM is pretty much an easy to use device. However, if you are not an electrician or electronics engineer, things can go wrong, which is quite normal. No need to beat yourself up too much. This is what happens all the time. One of the things that can go wrong with your digital or analog multimeter is a blown fuse.
In short, if you measure current inaccurately when your multimeter is set to amplifier mode, it could blow your fuse. The fuse can also blow if you measure voltage while the multimeter is still set to measure current.
So if you suspect you're dealing with a blown fuse and don't know what to do next, you won't find a better place than here. Here we will talk about everything related to fuses blown with a multimeter.
First things first; Why is the DMM fuse blown?
The fuse on the DMM is a safety feature that prevents damage to the meter in the event of an electrical overload. A fuse can blow for several reasons.
The multimeter has two ports for positive wires. One port measures voltage and the other measures current. The voltage measurement port has a high resistance while the current measurement port has a low resistance. Thus, if you set the pin to function as a voltage, it will have a high resistance. In such cases, your multimeter's fuse will not blow, even if you set it to measure current. This is because the energy is being depleted due to the high resistance. (1)
However, if you set the pins to the current function, it can create the opposite reaction, which will cause the fuse to blow. Because of this, you must be careful when measuring current. Parallel current measurement in extreme cases can lead to an immediate blown fuse because the ammeter has almost zero resistance.
Inaccurate current measurement is not the only thing that will cause a fuse to blow. This can also happen if you set up a multimeter to measure current and try to measure voltage. In such cases, the resistance is low, allowing current to flow in the direction of your multimeter.
In short, if you measure current inaccurately when your multimeter is set to amplifier mode, it could blow your fuse. The fuse can also blow if you measure voltage while the multimeter is still set to measure current.
Basic information about digital multimeters
The DMM consists of three parts: ports, display, and selection knob. You use the selection knob to set the DMM to various resistance, current, and voltage readings. Many brands of DMMs have backlit displays to improve readability, especially in low light conditions.
There are two ports on the front of the device.
- COM is a common port that connects to ground or to the minus of the circuit. COM port is black.
- 10A - This port is used when measuring high currents.
- mAVΩ is the port that the red wire connects to. This is the port you should use to measure current, voltage, and resistance.
Now that you know what goes where with regards to multimeter ports, how do you tell if you're dealing with a blown multimeter fuse?
Blown fuse detection
Blown fuses are a common problem with multimeters of all brands. In addition to equipment damage, blown fuses can cause injury. In such cases, your level of know-how will determine your safety and how you move forward. Many brands of multimeters and related devices come with impressive security features. However, it is highly desirable to understand their limitations and know how to avoid potential dangers.
A continuity test comes in handy when you need to test a fuse to determine if it's blown. A continuity test shows if two things are electrically connected. Electric current flows freely from one to the other if there is continuity. Lack of continuity means there is a break somewhere in the chain. You may be looking at a blown multimeter fuse.
The fuse of my multimeter has blown - what next?
If it burned out, it must be replaced. Don't worry; this is something you could do yourself. It is extremely important to replace the blown fuse with a fuse offered by the manufacturer of your DMM.
Follow these steps to replace the fuse on the DMM;
- Take a mini screwdriver and start unscrewing the screws on the multimeter. Remove the battery plate as well as the battery.
- See the two screws behind the battery plate? Delete them.
- Slowly slightly lift the front of the multimeter.
- There are hooks at the bottom edge of the faceplate of the multimeter. Apply a small amount of force to the face of the multimeter; slide it to the side to release the hooks.
- You have successfully detached the hooks if you can easily remove the front panel of the DMM. You are now looking at the inside of your DMM.
- Carefully lift the blown multimeter fuse and let it pop out.
- Replace the blown fuse with the correct one. For example, if the multimeter's 200mA fuse is blown, the replacement should be 200mA.
- That's all. Now reassemble the DMM and check the fuse is working using a continuity test to make sure everything is ok.
Having sufficient knowledge of how to use a multimeter is essential to prevent blown fuses. Pay attention every time you use the multimeter to avoid making mistakes that can get you into trouble.
Summing up
To do this, you have basic information about the ports of the multimeter (and their use). You also know why your multimeter's fuse might blow and how to avoid it. As you've seen, a continuity test can help you test a fuse to determine if it's blown. Finally, you learned how to replace a blown multimeter fuse - something pretty simple. It should be something doable in the future and we hope you feel confident about it after reading this article. (2)
Take a look at some of our articles below.
- How to Use a Cen-Tech Digital Multimeter to Check Voltage
- How to measure amps with a multimeter
- How to measure DC voltage with a multimeter
Recommendations
(1) energy – https://www.britannica.com/science/energy
(2) article - https://www.indeed.com/career-advice/career-development/how-to-write-articles
