My Multimeter was out of order. Here’s how I fixed it with some basic components

My Multimeter was out of order. Here’s how I fixed it with some basic components

The other day I was scratching my head in confusion. I was working on a circuit and it had bit of an issue. It was not giving the output that it should ideally give. I rechecked the circuit diagram and everything seemed fine. Somehow, I didn’t seem to find the problem in the circuit. After half an hour, I thought that it must be a connection issue.

I took out my multimeter and kept the selection dial at the connectivity tester mode. In case you do not know, here’s how a connectivity tester in a multimeter works. If you connect the two probe wires at the ends of a conducting path, it gives out a shrill buzzing sound. For example, if you keep one probe wire at one end of a simple conducting wire and the other probe at the other end of the wire, the multimeter buzzes. This indicates that current can flow through the section of the wire that you are testing.ย  If current cannot flow through both the probe wires, the multimeter is silent.

But for me, it was probably one of those bad days. The moment I put the selection dial in connectivity testing mode, the multimeter let out a buzzing sound. I took out the probes and reinstalled them. The problem persisted.

This is the closest thing you can get to what I call double trouble. I mean I was trying to get a problem fixed, but landed up in another. By now my whole attention had shifted from the circuit to the multimeter.

With an experience of over a decade in building and tinkering with electronics circuits, it did not take me long to figure out that a fuse in the multimeter had probably blown off. Fuses are protective devices which basically blow off when it senses that excess current can damage other key components. To know more about fuses, have a look at my Instagram post on fuses below. You can click on the image to view the post directly on Instagram.


Next, I took my screw driver set and opened the multimeter. Do you want to see how the inside of a multimeter looks like? The photo below shows how my multimeter looks after I have opened it.

Usually, fuses have a transparent capping. So, when the wire inside the fuse is broken, you can easily see through them and figure out if they have blown off or not. But, I was going through a terrible day. Remember? The capping on the fuses of the multimeter was made of a white-coloured material. I could not see through it. Can you believe it? And to add to the misery the multimeter that I use has two fuses. You can’t know which of them is blown off and which is ok. The picture below shows the two fuses in the multimeter. I have encircled them in red and put arrow marks so that you can easily identify them.

Now, the only way I could determine which of the two fuses had blown off is by using a connectivity tester. A fuse is nothing but a thin conductor running inside the two metallic ends. Ideally, current can flow through the fuse only when the thin conductor maintains it’s connection with both the metallic ends of the fuse. If you probe the two metallic ends of the fuse, a connectivity tester would buzz to indicate that the fuse is in right condition and current can flow through it. A blown off fuse has the connectivity cut off. Hence probing them would give us no results.

Now all I had to do was to get a connectivity tester to test both the fuses. But, I could not test the connectivity without the multimeter and the multimeter is what that has gone out of order!

This is too much problem especially when the day had just started. But engineers are meant to solve problems. Right? I took out my magic box. This is where I usually keep all the spare components and circuit elements. I took out the breadboard, a 7805 voltage regulator IC, an LED, a resistor and two male connecting wires.

Allow me to stop you here. I hope you already know how these basic electronics components work. But just in case you need some help, I have something amazing for you! I have developed a video learning program where I talk about the practical applications of some basic electronics components. Though it’s usually sold at a price of 499, I am giving this away to my readers for free! All you have to do is register with the details in the form below and I will send you a lesson everyday for 15 days. This is one of the best tutorials you can get on basic electronics and I can bet you on this. You have got nothing to lose. It’s worth a try. Trust me. You will love the content

Coming back to how I proceeded further to solve my early morning problem, here’s the schematic circuit diagram of what I built.

Schematic Diagram of Connectivity Tester

This emergency connectivity tester didn’t let out a buzz to signal connectivity. Instead, the LED glowed in case the two probe wires were connected to a current-conducting path.

When I connected the pins of the male connector wires together, the LED would glow indicating that two are electrically connected and current can flow through them. When I connected them to two ends of an insulator, it didn’t glow – indicating electrical discontinuity.

Here’s how the circuit of the emergency connectivity tester looked in real.

Enough of photos. Want to see it in action? Watch below.

India's Best Electronics Blog

After testing both the fuses, I found that in one of the cases the LED didn’t glow. It meant that the fuse had blown off. I just got a new fuse and replaced the faulty one. Now my multimeter started working perfectly as it should. I was elated.

But wait. I needed the multimeter to test the circuit I was designing. Right? Did I fix it? Well. That’s a story for another day. Stay tuned!

If you liked what you learnt, let me know in the comment section below. Didn’t like it? Let me know how I can make it better. Follow me on Instagram for daily updates on Electronics, circuits and robotics. It’s a goldmine of free information. Multimeter Lab is one of the largest and fastest growing electronics and related content repository on Instagram. Here’s the link to my Instagram page. Go check it out!


  • User Avatar
    Phide98 Posted February 26, 2020 1:56 am

    Is good i like that

    • User Avatar
      Pritam Nanda Posted March 11, 2020 1:29 pm

      Thank you for liking. ๐Ÿ™‚

  • ion Bar Posted March 9, 2020 10:14 am

    It’s a great content !

    • User Avatar
      Pritam Nanda Posted March 11, 2020 1:30 pm

      Glad that it helped. Thanks ๐Ÿ™‚

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