USB meter: Online Test

DSC_5340

Official specifications: I found this unit on Ebay at a dealer called sellerbible.



How does it look

DSC_5336

This usb meter has a cable on the usb input.

DSC_5364
DSC_5365

A switch is used to select between voltage and current display.

DSC_5338

In addition to the usb output, there is also a DC barrel connector for 5 volt input.
There is no markings on the device showing the DC connector is for 5 volt input.

DSC_7106

There is no screws, I could just pry the bottom off. I was a bit surprised about the inside with two circuit boards and lots of wires.

DSC_7107 DSC_7108

Four screws later and the circuit board is out together with the display.

DSC_7109

It looks like this device can be made in two version with different current resolution.
The black blob is the microprocessor, the raw chip is mounted directly on the circuit board.

DSC_7111

The current sense resistor is a piece of wire.

DSC_7112

Two quality trimpots to adjust current and voltage readings.



Measurements

Test



Temp734

M1:36,8°C, M2:36,4°C, HS1: 42,1°C
Notice that the cable is warm, i.e. the resistance in the cable will loose some power.

Temp735

M1: 39,4°C, HS1: 43,1°C



Conclusion

This usb meter works fairly well, but I would have liked some markings for the DC connector.
A acceptable device for people that want a manual V/A switch.



Notes

How do I make the test