few days ago I stumbled over a nice gimmick:
USB Current/Voltage detector
USB detector for measuring the USB interface.
Simply place the detector between source and load.
Immediately voltage and current are displayed alternating on the LED display.
The company produces quite decent quality, see linked Review
price: 6,99€* (~9,696 USD)
*Price per unit incl. VAT, plus (not included) shipping from Germany, NO trouble with customs within the EU
Payment is possible in BTC and € (bank transfer / SEPA).
shipping only with tracking and after prepayment.
We can ship worldwide for 6€ (~8,3227 USD) with registered priority airmailorder here: asicminer-shop.de
For orders with a valid EU VAT number (you can now enter your ID in the shop), or deliveries to non-EU countries
your price is 5.87€ or lessPlease contact us at
novat@asicminer-shop.de if you need assistance
———————————–
specifications:
Input Voltage: 4,5V ~ 6V
Input Current: 0 ~ 2,5A
Detection Precision: +/- 0,02V +/- 0,02A
Sizes: 64,5 x 21 x 14,5 mm
Weight: 20g
A detailed test can be found here:
lygte-info.dkWith a few more test I could draw some conclusions:
Volt was within +/- 0.01 on the display when not loaded.
Ampere is within +/- 0.02 on the display.
When loaded with 2.5A the displayed voltage is about 0.1 volt to low.
When loaded the voltage will drop, calculations shows the device has between 0.16 and 0.17 ohm resistance, this includes the measurement resistor, the internal connections and connections resistance (The 0.03 ohm from above is subtracted).
The voltage is shown for the input voltage, i.e. the voltage on the usb output that supplies the current to the device.
When voltage drops below 4 volt the precision will be reduced (The device is only supposed to work down to 4.5 volt).
The voltage readout is usable down to about 3 volt.
The device uses 0.025A (25mA) from the usb power, this current is not included in the display reading
The usb data lines are passed through, this means the coding on a usb output will be seen on the connected device.
---------
