esi / Tegam Resistance Line
esi (Electro Scientific Industries), founded in 1944 in Oregon is one of America's great technology and manufacturing companies. Now a leading supplier, of photonic and laser systems for microelectronics manufacturers, http://www.esi.com/, esi was originally founded as test and measurement company that pushed the envelope in the areas or resistance standards and measurement. In the 1990's they sold off their resistance product line to Tegam, www.tegam.com. In 2006, IET Labs was very fortunate to acquire rights to this legendary resistance line. With the esi line now complimenting IET's line, IET now supplies the world's most important impedance standards.
As it turns out, the founding of esi has a close connection to IET through General Radio. Frank Brown, one of esi's founders, and Melville Eastham, one of General Radio's founders, were both from Klamath Falls, Oregon. Brown owned a radio repair shop and Eastham would frequent that shop. In 1915 Eastham founded General Radio in Cambridge, Massachusetts, which was to become one of America's leading electronic companies. At the outbreak of World War II, General Radio was vital to the government's interests. Fearing that it might be attacked, the government told General Radio that they had to move part of their operation to another location. Eastham, who had been remembered being impressed by Frank Brown, moved the impedance bridge line to Oregon and asked Brown to head it. Brown relocated this operation to Portland and General Radio kept Brown busy throughout the war.
Subsequently, Frank Brown found ways to improve on the General Radio bridge designs and became General Radio's competitor.
esi offered the metrology community a number of impedance breakthroughs including:
The esi resistance line continues to be vital components of laboratories throughout the world . IET manufactures this line to the same or improved exacting standards set by esi.