Joulescope JS320 User’s Guide

Precision DC Energy Analyzer

Revision 1.3, last revised 2026 June 25.

• 1. Overview
  • 1.1. Affordable, easy-to-use, accurate and precise
  • 1.2. Key benefits
  • 1.3. Key features
• 2. Meet Your Joulescope JS320
• 3. Quick start
• 4. Specifications
  • 4.1. Absolute maximum ratings
  • 4.2. Mechanical
  • 4.3. Recommended operating conditions
  • 4.4. Specification conditions
  • 4.5. Current measurement specifications
  • 4.6. Voltage measurement specifications
  • 4.7. General specifications
  • 4.8. Parasitic effects specifications
  • 4.9. Software-controlled fuse specifications
  • 4.10. General purpose inputs and outputs
• 5. Host software
  • 5.1. Joulescope User Interface
  • 5.2. Scripts and automation
• 6. How to Connect Your Joulescope
  • 6.1. Measure only current (ammeter)
  • 6.2. Measure only voltage (voltmeter)
  • 6.3. Measure power supply provided
  • 6.4. Measure target device consumption
  • 6.5. Measure subsystem consumption
  • 6.6. Measure higher voltages
• 7. Theory of operation
  • 7.1. Ammeter
  • 7.2. Voltmeter
  • 7.3. Host Computer
  • 7.4. Power, Energy, Charge, and Statistics
  • 7.5. High impedance / low leakage
  • 7.6. Electrical isolation
• 8. How to swap the front panel
• 9. GPI & GPO
• 10. Fuse
  • 10.1. Max Fuse
  • 10.2. Range Fuse
  • 10.3. User Fuses
• 11. Electrical Isolation
• 12. Filters and Frequency Response
  • 12.1. Analog Filter
  • 12.2. Downsampling
• 13. Typical Behavior
• 14. Maintenance
  • 14.1. Verification Procedure
  • 14.2. Offset Calibration
• 15. Ordering Information
• 16. Compliance
  • 16.1. United States
  • 16.2. Canada
  • 16.3. Europe
  • 16.4. Safety
  • 16.5. RoHS Directive 2011/65/EU, 2015/863/EU
  • 16.6. Country of origin
• 17. Warranty
• 18. Intellectual Property
• 19. Change log