Leeds & Northrup 4398-M Double Ratio Set: Measuring PPMs the old-fashioned way

curiousmarc 3wOO4L

CuriousMarcWe rescue a high-end Kelvin bridge, that was supposed to measure resistances to a fraction of parts per million. It cost the equivalent of $28,000 in today’s money. Will it still work, or have the ppm’s escaped the box since the 1960’s? Stuff that supports the channel: – Support us …

Read More

From: Retro Roundup