REJOE Power monitor EMK850S+ Review & Teardown | Voltlog #415

Welcome to a new video, this will be a review & teardown of this power profiler device so this can be useful if you are trying to measure the power usage of a particular board that you are working on. It can internally generate an adjustable voltage power supply rail which it outputs on these terminals, you use that to power the device under test then by using the supplied PC software you can analyze the power usage of your device in great detail. 

As you may remember I also have a Joulescope which is an awesome piece of equipment, high resolution, high dynamic range for doing the same kind of analysis but it does not include the power supply. This guy with its included power supply is closer to something like an otii arc, cause that one also include the power supply so I might make some comparisons in terms of specs with these devices during the video.

Inside the box you get a power brick which feels low quality, a mains IEC cable with an adapter for European plugs, we won’t be needing these as I can use my own IEC cable with the proper plug, and a set of short test leads with banana plugs and J clips, The cable feels nice, flexible but the connectors are of low quality and you are likely to encounter problems if you will be using this types of clips long term so I will be replacing these as well. In my opinion, instead of including cheap test leads, you might not include any at all. Saves the final user the trouble of dealing with bad test leads.

The front panel features the two output banana plugs widely spaced apart, two rotary encoders crammed together and a couple of 7 segment displays for voltage and current so that you can get readings independent of the PC app. On the back we get the DC 12V input and the USB connection for the computer plus an on/off switch. They had plenty of space on the front panel so I think it would be nicer to have the on/off switch on the front. And the two potentiometers spaced wider apart. The model number for this unit is EMK850S+.

They don’t tell much in terms of specs but they mention Input Voltage 12V DC, Output voltage 0.5-12V,

Measure Range: 0.1μA – 2A, provides μA resolution current measurements with a sample rate of up to 10 ksps. No claims on accuracy as of now but maybe they’ll add those later, as I said this is a new product. If we compare it to the joulescope which has a 2Meg sample rate and 1nA resolution the TechRejoe unit is clearly lower specced but also less expensive