Multimeter/Voltmeter without battery?

Hi guys,

I always get frustrated when I come in and find a dead (leaking) battery on tools or devices I don’t use often, I should probably remove the battery…
Anyway i do not like batterry.

The last lime I bought, I tried to connect it to an adapter 9-12v plugged into the wall socket but I ended up burning my voltmeter like this:
image

Now I’m going to buy a new one and I’d like one that doesn’t require a battery at all. One that I can plug into the wall or computer.

I sow this:
image
But the usb is not practical for electronic testing (Arduino stuff).

I remember i build one with arduino a long time ago but too lazy to build something and want something more professional.

Do you know one to buy?
Thanks

Bench multimeters start at about $110. You can find used ones for about half of that.

You could also take some $25 entry-level multimeter and add a USB port and some buck or boost converter and then power it via USB, for example.

For what it’s worth, the battery in my $20 DMM lasts for a couple of years. It’s completely off when it’s off. My sound level meter, on the other hand, slowly drains the battery over time. That makes it also more likely that the battery will start to leak.

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I’m desapointed, I searched and did not found so i ordered one with battery this morning, i’ll find later some rechargeable battery and stick with it until my Multimeter get die.

The power needs to be isolated and very well filtered, and that’s an important part of a bench multimeter. It’s one reason they cost more.

For a battery-operated multimeter, a buck or boost converter will have high frequency voltage ripple that needs to be properly regulated, because otherwise the ripple in the supply voltage will likely induce noise that affect measurement. By contrast, batteries are not noisy power supplies, and it would be a waste to put extensive filtering in place when designing an instrument meant to run off batteries.

You would also want to make sure that the power supply was isolated. A battery-operated multimeter is isolated by not being connected to other circuits. A typical buck or boost converter is common ground, not isolated. So if you converted a battery-operated multimeter to use a USB power supply, even if you filtered the input voltage well enough, if you had a common ground with a circuit you were testing you could destroy that circuit, the multimeter, or both.

A multimeter will have a safety rating involving electrical isolation. If you hack a multimeter to make it not battery-powered, you are defeating that safety rating and taking full personal responsibility for the consequences of lack of isolation. Depending on what you are measuring, this could be a fatal mistake.

Therefore, just use batteries, rechargeable or otherwise, or a bench multimeter designed to provide this safety.

I hope this makes it more obvious why you don’t find a lot of multimeters that meet your specification. :relaxed:

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The multimeter that you show above does not have a timed power off and therefore if you leave it on it kills the battery.
As @tomatsu suggests get meter off amazon that has an autopower off and the batteries last a long time no need to externally power them.

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I suspected that there must be a real reason for everyone to offer only batteries based because it would be silly to limit it to battery only.
Thanks for the great explanation!

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