Four Point Probe Experiment

Quick Measurements Within or Amongst Samples

Measure a wide range of resistivities at various temperatures with a high degree of accuracy. The widely-used standard of the four probe method is made even more accurate with this experiment. The collinear arrangement of these four probes removes error due to contact resistance in the electrical measurement of semiconductors by the use of two extra contacts (probes) between the current contacts. The contact resistance may be high compared to the sample resistance, but as long as the resistance of the sample and contact resistances are small compared with the effective resistance of the voltage measuring device (potentiometer, electrometer or electronic voltmeter), the measured value will remain unaffected. Because of the use of pressure contacts, this arrangement is specifically useful for quick measurements on different samples or sampling different parts of a sample. Everything required for measurements is provided, including the four probes arrangement, PID controlled oven, constant current source, and DC microvoltmeter. The constant current source provided features CCS-01 for low to medium resistivity samples and LCS-02 for high resistivity samples. 110/220 V, 50 Hz/60 Hz.