Current sink capabilities


Is it safe to sink current into the Arc when it is set up as a voltage source? I see there is a generous current sink spec in the datasheet, but there is also a special battery profiling mode in the scripting environment. Do I need to enter a special mode, or take special precautions, before sinking current into the Arc?

I also noticed that with Autoranging turned on, large negative currents would clip rather than triggering a switch to the high range. Is this an intentional limitation?

And one last question - if I accidentally overvoltage the external power supply (12 V instead of 9V for instance), what kind of fireworks can I expect? Should I be fitting an external clamping diode when using a lab supply to power it, or is there internal protection against this sort of carelessness?


Hi James,

The Otii Arc will always be ready to sink up to around 500mA in voltage source mode, you do not need to set it in current sink mode for this.

Yes, negative current spikes will clip the measurement. The range is set by how much current Otii Arc should sink and it will not switch from low to high range due to a negative spike.

The Otii Arc has an internal TVS diode to protect the rest of the circuits and it starts to conduct just above 12V. However, I do not recommend that you use this as your protection, so an external diode sound good if you know that this might happen.

Best regards,