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# Electrical Isolation

The Joulescope is electrically isolated between the USB interface and the
IN/OUT sensor. Joulescope is rated to ±48V between USB ground and any of IN+,
IN-, OUT+, and OUT-. The individual component ratings far exceed this
specification. The components are:

| Part #         | Mfgr         | Description      | Isolation working   | Isolation 60s   | Isolation 1 s   |
|----------------|--------------|------------------|---------------------|-----------------|-----------------|
| 760390014      | Wurth        | Transformer      | 400 VRMS            | 2500 VAC        | 3125 VAC        |
| Si8661BB-B-IS1 | Silicon Labs | Digital isolator | 445 VRMS            |                 | 4500 VRMS       |
| TLP2361(TPL,E  | Toshiba      | Opto isolator    | 500 VRMS            | 3750 VRMS       |                 |

The printed circuit board (PCB) clearance between the isolated sensor side and
the USB host side is 1 mm. The use of an aluminum enclosure effectively limits
the isolation voltage and requires that USB chassis ground surrounds the
sensor edges. If you use Joulescope in a custom application without the
standard enclosure, the four chassis ground rails (2 top & 2 bottom) can be
cut around the isolation line to give a 4 mm PCB clearance between the USB
host side and the sensor side.