Antique Wheatstone Bridge Slide Wire Rare Leeds & Northrup Co. #4203

Description

Antique Wheatstone Bridge Slide Wire
Rare Leeds & Northrup Co. #4203
Please look at the pictures they are part of the description
Condition:  Generally good, the oak board could use a sanding and stain, the device has the usual wear and oxidation.  Painted number (1216) under board, probably original owner’s identification. Missing Slide and (3) bakelite terminal nut knobs.
Sold only as a vintage decorative artifact and curiosity, not for use with electricity or other power source.
A Wheatstone bridge is an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit, one leg of which includes the unknown component. The primary benefit of the circuit is its ability to provide extremely accurate measurements.
The Wheatstone Bridge circuit is nothing more than two simple series-parallel arrangements of resistances connected between a voltage supply terminal and ground producing zero voltage difference between the two parallel branches when balanced.
A Wheatstone bridge circuit has two input terminals and two output terminals consisting of four resistors configured in a diamond-like arrangement as shown. See last picture, this is typical of how the Wheatstone bridge is drawn.
Leeds & Northrup was founded in Philadelphia by Morris E. Leeds as Morris E. Leeds & Company.  Dr. Edwin F. Northrup, an educator, scientist and engineer, joined the partnership in 1903.  The company produced high quality electrical measuring laboratory instruments.  Until then, the best precision instruments came from Germany, but Leeds & Northrup provided an American-made alternative.  The company produced a number of innovative measuring devices for education, science and industry, including the world’s first electronic recorder in 1929.  Since 1978, the company has been resold and renamed.  Since 1995, it has been part of the multi-national  Heraeus Electro-Nite Co. and is now known as L&N Metallurgical Products Co., producing industrial molten metal sensors and instrumentation for the international market.
Maker’s metal label: Leeds & Northrup Co./ Philadelphia/ Ser. No. 419889/ Cat. No. 4203/ Made in U.S.A.