Perform Resistivity Measurements and Conduct Sample Determinations
Determine the number of carriers present in a sample, identify carrier densities and mobilities present in a sample, plus perform resistivity measurements with this experiment. The setup includes two hall probes — one Germanium (Ge) crystal and one Indium Arsenide crystal (InAs). The Germanium single crystal with four spring-type pressure contacts is mounted on a sunmica-decorated Bakelite strip. Four leads are provided for connections with measuring devices. The Indium Arsenide crystal with four soldered contacts is mounted on a PCB strip and covered with a protective layer. The Hall Element is mounted in a pen-type case and a 4-core cable is provided for connections with the measuring device and current source. A digital Hall Effect Set-up (DHE-21) is also provided with an intersil single chip A/D Converter ICL 7107. Providing a high level of accuracy, this digital setup features auto zero to less than 10 μV, zero drift of less than 1 μV/°C, input bias current of 10 pA maximum, and roll over error of less than one count. Accuracy is ±0.1% of reading ±1 digit. Both EMU-75 and EMU-50V electromagnets are provided along with two constant current power supplies — DPS-175 and DPS-50. Specifically designed for Hall Probe, these power supplies provide 100% protection against crystal burn-out due to excessive current. The DC power supply is highly regulated and practically ripple-free. Accuracy is ±0.2% of the reading ± digit. Set up also includes a digital gaussmeter, DGM-102.
110/220 V; 50 Hz/60 Hz.
