A wire carrying the AC current to be measured must be passed through the hole in the large, black current transformer component. For safety reasons always use an insulated wire. See safety warning.

The SPice 10204 is factory calibrated for 5A full scale. We calibrate using the mains power supply and a true rms meter. The circuit is average reading.

If you want a lower current full scale you can pass the current carrying wire through the transformer hole more than once. For example, if you wind the wire around the transformer so it passes 5 times through the hole, you will get 1A full scale. Don’t overlook safety insulation requirements if you do this.

If you want a higher current scale, you can use an external current transformer as a “front end”. Most commercial current transformers sold for electrical use have full scale output currents of 1A or 5A. Using an external scaling transformer has the added advantage that it becomes the primary safety isolation barrier (providing you use a device with the appropriate approvals).