# Measuring 185 µΩ In Circuit

To measure resistance, you usually have to take the resistor to be tested out of the circuit, and sometimes that’s impossible. If you’re using a multimeter, measuring very small resistances is difficult to say the least. Combine both these problems – measuring microOhms in-circuit – and you have a problem that’s perfectly suited for the Mooshimeter.

Announced just a few weeks ago, the Mooshimeter is a two-channel multimeter that communicates with your cell phone over Bluetooth. It’s perfect for measuring current and voltage simultaneously, all while being tucked away in some place that’s either dangerous, inaccessible, or mobile.

The Mooshimeter team put together a great example of what can be done with their meter by measuring the resistance of a car battery grounding strap while behind the steering wheel. To do this, they put alligator clips across the grounding cable and clamped on a current meter.

Inside the car, they whipped out their cell phone and looked at the Mooshimeter’s output for the voltage and current measurement. The Mooshi app has an IV curve (with linear regression in the works), so simply dividing the current and voltage gives them the resistance of the battery’s grounding cable.

It’s a very cool and extremely simple demonstration of how cool the Mooshimeter actually is. Video of the demo below.

## 17 thoughts on “Measuring 185 µΩ In Circuit”

1. genki says:

I thought milli- has m stuffix and u- stuffix is micro? Title reads micro-ohms but the body reads milli-ohms.

1. Rob says:

Mu ( µ )is definitely micro.

2. denis says:

I hate to be one of those people, but two posts about an overpriced commercial product doing its job normally?

1. Elias says:

Overpriced? You can’t event get a decent DMM for that price.

1. John says:

One can get a 6.5 digit HP 3455A/3456A or a Solartron/Schlumberger for that money very well. And these DVMs have a real reference so all the 21 bits of resolution are usable, not a 24 bit ADC with a zener diode reference joke.

1. George says:

Why are you comparing a portable two channel meter to a single channel benchmeter? My Prius is a terrible 18-wheeler…

2. David says:

Uni-T UT61E is a great DMM with RS232/USB for \$56; UT136B is decent for \$16.

1. Elias says:

I think we have quite a different concept of decent :)

1. David says:

If you think the Mooshimeter is “decent” and the Uni-Ts aren’t, you don’t have a consistent concept of “decent”.

3. Torque says:

I hope you’re joking, because even a decent multimeter that can even precisely real type-K thermocouples and measure capacitance and inductance of most hobby sized components can be bought for that price.
Paying out of the ass for Bluetooth 4.0 connectivity, which only recent smartphones sports.

Over-engineering the wrong part of the design, bang-for-the-buck must be a alien concept to those behind the Mooshimeter

2. Ren says:

I bought my GenRad BugHound for about \$2 at auction… B^)

3. Patrick says:

i wonder what it would take to get a UL listing