What is it about?

We wanted to measure the effectiveness of an air ioniser, for evaluating its use in weather modification. Measuring the ion current conventionally requires a complicated system. Our method is simple - use the ion current to light a LED, and measure its brightness remotely.

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Why is it important?

New applications of air ionisers are being found in aircraft propulsion and weather modification, beyond their typical use in air purification. Assessing their effectiveness generally requires a current measurement at high voltage, and a LED provides an unexpectedly simple way to do this.


LEDs are amazing devices as efficient sources of light, but can be repurposed in new ways too. We have found we can use a LED to sense electric currents flowing at high voltage, though using the infra-red light generated to indicate the current. The isolation inherent in optical communication avoids a direct connection to the high voltage. Even microamp currents, lighting the LED only dimly, still provide a detectable optical output. This has greatly simplified our monitoring system.

Professor Giles Harrison
University of Reading

Read the Original

This page is a summary of: Isolated corona current monitoring using a compensated light-emitting diode as an unpowered sensor, Review of Scientific Instruments, September 2023, American Institute of Physics,
DOI: 10.1063/5.0170176.
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