microK²

Twenty years after the first one, we and Isotech faced the question every long-running product eventually raises: extend an ageing design, or start again. Processing had moved on, interfaces had moved on, and the original microK was still selling on the strength of decisions taken in 2004.

We started again. microK² is a re-engineered platform rather than a refresh, and the first two models arrived in late 2024. Two more followed to complete the family, at which point Isotech retired the original microK after nearly two decades in service.

The thread back to 2009 is the interesting part. Parallel analogue processing, the input-noise technique we had to invent to get the microK 100 into primary standards work, is what the ELITE and the 60 use now. The ELITE is guaranteed better than 30 ppb across the entire ratio range, which is 30 µK over the whole SPRT range and 7.5 µK at the water triple point, and the 150 and 300 bring the same architecture to secondary laboratories and ISO 17025 work. Isotech’s published figures run from 30 to 300 ppb across the family.

Everything else grew where it needed to. Four input channels instead of two, expandable to 93 through microsKanner units. Three internal reference resistors instead of one, expandable to eight. Keep-warm current up to 14.2 mA, which widens the range over which self-heating can be determined. A ten-inch anti-glare touchscreen, and enough internal memory that logging no longer needs a computer attached.

Two decisions from the original survive untouched. It is still solid-state throughout, with no moving parts, because relays were the wrong answer in 2004 and are still the wrong answer. And it is still drift-free by construction, which is the property that got the microK into national measurement institutes in the first place.

Every microK² is checked during production on an Automatic Resistance Bridge Calibrator, which we production-engineer and manufacture for Isotech. It is what settles the ELITE’s guaranteed figure, and what every other unit in the family is measured against. The tooling and the instrument it validates came out of the same twenty years.