• Yocto-Watt

This device is a digital watt-meter allowing you to monitor the power consumption of electrical devices. Its works with both AC and DC current. Regarding AC current, the device computes the real power consumption (not just the product of RMS voltage and current), so it can be used to monitor inductive loads. The Yocto-Watt can compute the power consumption during a given lapse of time. Accuracy is 1mWh, 1%.

This device is isolated, which means that the sensor part is electrically disconnected from the USB part: you can measure any voltage difference between -250V and 250V, without risk of frying your computer. The module provides immediate reading on USB and can also store measures on the device internal flash for later retrieval when connected again by USB.

This device can be connected directly to an Ethernet network using a YoctoHub-Ethernet, to a WiFi network using a YoctoHub-Wireless-n and to a GSM network using a YoctoHub-GSM.

Yocto-Watt Yocto-Watt Yocto-Watt

USB cables and enclosures to be ordered separately.


Hardware release:Rev. D
Product name:Yocto-Watt
USB connector:micro-B
Max current (Cont.):16A
Refresh rate:10Hz
Measuring range (I):-16...16A DC/rms
Measuring range (U):-250...250V DC/rms
Max working voltage:250V r.m.s.
Accuracy (AC, 50Hz/60Hz):0.02 W / 1.5%
Accuracy (DC):0.002 W / 1.5%
Measurement category:Cat II
Protection class, according to IEC 61140:class II
USB isolation, clearance dist.:3.8mm
USB isolation, creepage dist.:3.8 / 6mm
USB isolation, dielectric strength (1 min.):3kV r.m.s.
Normal operating temperature:5...40Ѓ
Extended operating temperature2:-30...85Ѓ
Power derating:0,67A/Ѓ above 61Ѓ
Supported Operating Systems:Windows (PC + IoT), Linux (Intel + ARM), macOS, Android
Drivers:Driverless, no driver needed
API / SDK / Libraries:C++ Obj-C C# VB.NET UWP Delphi Python Java Android LabVIEW
API / SDK / Libraries (TCP only):Javascript Node.js PHP
RoHS compliance:RoHS III (2011/65/UE+2015/863)
Suggested enclosure:YoctoBox-Watt-Transp
Harmonized tariff code:9032.9000
Made in:Switzerland

1 These specifications are for the current hardware revision. Specifications for earlier revisions may differ.
2 The extended temperature range is defined based on components specifications and has been tested during a limited duration (1h). When using the device in harsh environments for a long period of time, we strongly advise to run extensive tests before going to production.

Accessories and related products

YoctoBox-Watt-Transp, Plastic enclosure for the Yocto-Watt sensorUSB-A-MicroB-50, USB 2.0 type A to Micro-B data cable, 50 cm


User manual (HTML)
User manual (PDF)
Product brief
3D file (STEP)
RoHS certificate
Most recent firmware44118 (03/10/2021)
Programming libraries44175 (03/12/2021)
Command line API44175 (03/12/2021)
VirtualHub application44029 (02/26/2021)


  • Brand: Yoctopuce
  • Product Code: YWATTMK1
  • Availability:
  • $150.00