The resistivity measurements of semiconductors can not reveal whether one or two types of carriers are present, nor distinguish between them. However, this information can be obtained from Hall Coefficient measurements, which are also basic tools for the determination of carrier density and mobilities in conjunctions with resistivity measurement.

Hall Effect set-up includes

• Hall Probe (Ge. crystal mounted on a PCB).
• Electromagnet 10,000 gauss.
• Power supply for electromagnet.
• Constant current power supply with two digital meters digital 
• millivotmeter 0-200mV sensitivity ± 0.1mV. Auto polarity digitalmilli 
• ampere-meter 0-20mA , sensitivity ± 0.01mA.
• Digital Gauss meter with Hall Probe, 20KG .
• Wooden stand for probes.