Talking About Joulescope Schematic: How Does It Measure Voltage and Current So Precisely?

Why It Matters

Engineers can use the JS320 to profile and optimize device power consumption across wide dynamic ranges instantly, enabling longer battery life and faster hardware iteration. Improvements in ADC and front-end integration reduce measurement complexity and improve accuracy for test-and-measurement and low-power product design.

Summary

The video explains how the Joulescope family—culminating in the new JS320—achieves precise simultaneous voltage and current measurements from nanoamps to 10 amps by combining a shunt-based analog front end with fast, high-resolution ADCs and TI signal-chain components. Presenters describe the instrument's low burden voltage, seamless high-dynamic-range auto-ranging, and on-board processing that multiplies voltage and current to derive power, charge and energy in real time. They walk through schematic-level design choices—shunt sizing, amplification, filtering, and ADC selection (including TI's ADS and L14 series)—that enable instruction-level current visibility without device brownout. The discussion also covers trade-offs and future directions like integrating anti-aliasing and more digital features into ADCs to simplify front-end design.

Original Description

This video breaks down the schematic circuit behind how the Joulescope achieves precise voltage and current measurements.

Special thanks to Matt Liberty, creator of Joulescope, and Josh Brown from Texas Instruments.

Links:

- Matt's LinkedIn: https://www.linkedin.com/in/mattliberty/

- Matt's website: https://www.joulescope.com/

- Joulescope 3D view: https://download.joulescope.com/products/JS320/JS320-K000/3d_ti/index.html

- TI Test and measurement website: https://www.ti.com/applications/industrial/test-measurement/overview.html?HQS=multi-tech-inno-precisiontm_tm-show-pp-inf_robert_joulescope-ww_en_awr

- TI's White Paper on Optimizing Chopper Amplifier Accuracy: https://www.ti.com/lit/wp/sboa586a/sboa586a.pdf?HQS=multi-tech-inno-precisiontm_tm-show-whip-inf_robert_joulescope-ww_en_awr

- Bluetooth board: https://www.ti.com/product/CC2340R5?HQS=multi-tech-inno-precisiontm_tm-show-pf-inf_robert_joulescope_CC2340R5-ww_en_awr

- Ask your questions about electronics here: https://fedevel.com/assistant

- Easy search through my videos: https://fedevel.com/hw-assistant

- Learn more about electronics, check out our online courses: https://fedevel.com/courses

Chapters:

00:00 What is this video about

01:52 About Matt and Joulescope

07:08 Schematic - Analogue front end for current measurement

19:48 Schematic - Analogue front end for voltage measurement

21:22 ADC circuit explained

35:38 Testing and validation

50:23 Zero drift op amps

59:14 Layout and placement challenges

1:05:04 Measurement demos

1:11:09 Bluetooth power measurement demo

1:20:26 3D model of the board to show component placement

1:25:26 Joulescope JS320

1:28:27 Matt's website

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