MINI Altoids battery-less Voltmeter!!

Hey guys, i have a new member of my measurement arsenal! My new, altoids (mini) voltmeter! The range on this is 3 volts - 30 volts. It's perfect for testing continuity and is very convenient, both sizewise and how it has alligator clips for easy testing!

The best part...No Batteries! It's battery-less!

Now,some pics!

The exterior:


Interior, kinda sloppy, but watever!


The clips:


Attached to my newest host kit, testing lead continuity


Press the tailswitch and the display lights up with a reading! 4 volts!


Up close LED display!


I love this voltmeter and plan to continue using it!
Any questions are welcome
Thanks for looking!

For those that don't know what's going on here, the meter steals power from whatever it measures. This means the voltage range is only ~3-30V, and it only works with low output-impedance voltage sources. In other words, higher voltage batteries and wall warts only. "Continuity" requires a battery. It has its place, but it makes a terrible "general purpose" meter.

Just keep in mind that since it is powered by the circuit under test, the reading will drop in certain conditions so keep that in mind.

But for testing batteries, it is great!

edit: cyp beat me to it.

Yep, this is basically a low impedance volt meter, which means that there will be a voltage drop caused by the loading the meter imposes on the source under test. I'm curious about what the actual current draw of the meter is. Novelty is this pony's one trick. Generally the higher impedance of the meter the better it is considered, all other factors aside. For example folks who work on radiation detection equipment typically prize one gigaohm and higher impedance meters.

When I read the title I thought it was going to be solar/induction charged super-cap powered.

If it's similar to one I have used before, current consumption is about 50mA.

Sigurthr said:

When I read the title I thought it was going to be solar/induction charged super-cap powered.

Click to expand...

*sigh
I wish it was nuclear powered

I don't think so, heh. The NRC would at the very least treat you like the radioactive boyscout 2.0, and that is no picnic.

in theory RTGs can be made pretty small, but the problem is that it is 1) uneconomical, and 2) inefficient. The radiative cooling needed for a passive system is quite complex, and if you try to actively cool it well then you are chasing your tail. Nuclear batteries can be made but the beta flux needed to generate measurable currents borders on lethal without proper shielding. The first generations of pacemakers used Pu batteries, and while safe, cost a fortune, and are illegal to own if not currently implanted.