The first four‑point probe head. Continuously shipped since 1968.
A short, surprisingly long history — and the reason engineers keep coming back to Signatone.
The Clerx idea
In 1955, semiconductor research labs measured sheet resistance with a tangle of four loose probe tips, springs, and machine‑shop fixtures. Pete Clerx — a Philips Semiconductor engineer who had been hand‑building probe assemblies for years — packaged the geometry into a single self‑contained head: four colinear tips, equal spacing, equal contact force, on a swappable mount.
It looked obvious in hindsight, the way good engineering does. Within a decade every analytical lab in the Western world was running one. By 1965 Clerx had founded Signatron — the proprietorship that became Signatone — to build them at volume.
Built in California
Signatone has been family‑owned since 1976 and has manufactured in California since 1982. The team is small — engineers and machinists who answer their own phones, sign off on their own work, and ship from the building they designed it in.
That structure is intentional. It's what lets us turn around a custom configuration in eight weeks instead of eight months, and it's what lets the engineer who designed your station also be the engineer who picks up when you call.
Sixty years in, still answering the phone.
If you're running an older Signatone station — even a hand‑built S‑1160 from the 1970s — call us. We still have the schematics, the parts, and the people who built them.