Leeds & Northrup 4300 Adjustable Resistance Standard Slide Wire 0.01 Ohm Lab

Leeds & Northrup 4300 Adjustable Resistance Standard Slide Wire 0.01 Ohm Lab

The Leeds & Northrup 4300 is a precision slide wire Adjustable Resistance Standard designed for use as a low-resistance calibration reference in potentiometric and bridge measurement systems. It features a continuous resistance wire strung along a calibrated ruler rail, with a sliding contact wiper that traverses the wire to select any resistance value up to 0.01 Ohms. Three fixed binding post taps — labeled.003,.004, and.005 Ohms — are mounted on the black anodized top panel alongside the slide wire assembly. The instrument sits on a solid wooden base and is protected by a clear acrylic/plastic dust cover.

Specifications & What's Included

• Manufacturer: Leeds & Northrup Co., Philadelphia, Pennsylvania
• Catalog No.: 4300
• Type: Slide Wire Adjustable Resistance Standard
• Maximum Resistance: 0.01 Ohms
• Fixed Resistance Taps:.003,.004, and.005 Ohm binding posts on top panel
• Contact Mechanism: Sliding wiper cylinder on continuous resistance wire
• Scale: Calibrated ruler rail for precise wiper positioning
• Base: Solid wood
• Cover: Clear acrylic/plastic dust cover included
• Country of Manufacture: USA
• Coiled lead wire attached to sliding contact

Applications

Leeds & Northrup was one of the foremost American precision instrument manufacturers of the 20th century, producing potentiometers, resistance standards, and bridge measurement equipment used in primary-standards laboratories, university research, and industrial calibration facilities. The 4300 Adjustable Resistance Standard is a classic slide wire instrument of the type used in Kelvin bridge and Wheatstone bridge measurements, where a precise, continuously variable low resistance is needed as a reference leg. These instruments were standard equipment in electrical metrology labs and are still sought today by calibration engineers working on legacy bridge circuits, as well as by instrument collectors and museum conservators. The slide wire design — a tensioned resistance wire traversed by a wiper contact — was a hallmark of mid-20th century precision measurement practice, predating digital decade resistance boxes. This example, made in Philadelphia and bearing the classic Leeds & Northrup Co. nameplate, is a representative piece from that era of American precision instrument manufacturing.