U13114 John Deere:disk PLATE, wagon tongue, bottom (YR. 53-)

3B Scientific U13114 Hall Effect Basic Apparatus
Basic apparatus for attaching contacts and supplying voltages to germanium crystals on printed circuit boards || For experiments on the measurement of hall potentials and conductivities at different temperatures || Stem for setting up the apparatus between the pole-shoes of the transformer assembly kit || Integrated adjustable constant-current source and amplifier || Matching and cut out functions for offset voltages