1. Overview#

1.1. Affordable, easy-to-use, accurate and precise#

Multimeter view

Oscilloscope view

Multimeter view

Oscilloscope view

Applications include:

  • Microprocessor and microcontroller power profiling and optimization

  • Hardware power optimization

  • Microcontroller and device sleep current optimization

  • Hardware and software troubleshooting

  • Software characterization and interrupt service routine profiling

  • USB inrush and suspend current pre-compliance testing

  • General-purpose current, voltage, power, charge, and energy measurement

The Joulescope™ JS320 is the most affordable and easy-to-use precision DC energy analyzer. It measures current and voltage, then computes power and energy. Many modern battery-powered devices and IoT devices have a high dynamic current range, which makes accurate measurement difficult. When “sleeping” the devices consume nanoamps (nA) or microamps (µA), but when active, they consume milliamps (mA) or amps (A). Joulescope combines high-speed sampling and rapid dynamic current range switching to provide accurate and seamless current and energy measurements, even for devices with rapidly varying current consumption. The unprecedented accuracy and low-cost of Joulescope allows every engineer on the team to measure the energy consumed by the target device during development. Joulescope provides rapid feedback on how changes affect the overall product battery life.

Joulescope displays instantaneous voltage, current, power, and energy, like a multimeter. The multimeter provides a quick and easy summary of the present state of your device.

Joulescope displays waveforms of voltage and current over time, like an oscilloscope. This oscilloscope view allows you to identify and to troubleshoot dynamic behavior and short events, including inrush current, event handlers, and tasks.

1.2. Key benefits#

  • Dynamic range: The Joulescope JS320 accurately measures electrical current over ten orders of magnitude from amps down to nanoamps. This wide range allows accurate and precise current measurements for modern devices. Sleep modes are often just nanoamps (nA) or microamps (µA). Active modes are often milliamps (mA) or amps (A).

  • Low voltage drop: Most multimeters and current meters have a significant voltage drop (sometimes called burden voltage or insertion loss), which affects the actual voltage delivered to the device under test. Joulescope has a total voltage drop of 25 mV at 1 A, which keeps your target device running correctly. Joulescope’s extremely fast current range switching maintains low voltage drop even under rapidly varying current demands.

  • Makes the invisible visible: The JS320 measures current and voltage 2 million times per second with 200 kHz bandwidth. This high sampling rate makes the power consumption of interrupt service routines, inrush currents, and other short events visible.

  • Easy to use: The JS320 reports cumulative energy and charge consumption along with real-time current, voltage, and power. The multimeter view clearly shows the most recent value, while the oscilloscope view allows you to explore changes over time. Much simpler and more accurate than anything in its class!

  • Customizable: The host software is open source on GitHub. You can also swap the banana jack front panel with front panels that have other connector types. The front panels are open source on GitHub.

  • Portable: The JS320 fits in your backpack and only needs a small part of your desk. It provides precision measurements in a portable, unintrusive form factor.

  • Affordable: The Joulescope JS320 is affordable and priced so that every developer on the team can have one at their desk. With such convenient access, Joulescopes allow developers to see the impact of their changes on energy consumption immediately. Developers can make informed choices to account for battery life during design. Eliminate power consumption surprises during final product testing!

1.3. Key features#

  • ±15V voltage range

  • ±3A current range, continuous

  • ±10A current pulses (<10 ms, < 3A average per second)

  • Down to 0.1 nA resolution, equivalent to 36-bits of dynamic range

  • Synchronously measures voltage and current at 1 million samples per second, 24-bit

  • 200 kHz linear phase bandwidth

  • 300 kHz compensated bandwidth with optional digital filter

  • Rapid 1 μs switching between shunt resistors

  • Enwavify™ technology for consistent, accurate measurements through current range changes

  • Computes power, energy, and charge

  • Operates with minimal voltage disturbance between Current + and Current – ports

  • Up to ±48V common-mode voltage between USB ground and sensing ports

  • 4 general-purpose inputs and 2 general-purpose outputs

  • 1 BNC trigger configurable for either digital input, digital output, or analog output

  • Programmable on/off for power cycling the target device and measuring inrush currents

  • USB 2.0 high-speed host connectivity with USB C connector

  • Host software support for Microsoft® Windows®, Apple® macOS®, and Linux®

  • Host software user interface provides real-time graphs of current, voltage, and power over time

  • Python library and scripting provided

  • Host software is open source and available on GitHub

  • Swappable front panel with open-source designs on GitHub

  • Firmware upgradable

See Section 4 for the full specifications.