The Keithley 3765 Hall Effect Card is intended for those who want to assemble their own economical Hall test systems. It can also form the foundation of a full Hall Effect system. Used along with the free software, the Keithley Hall Effect Test Suite (KHETS), the 3765 is easily paired with Keithley DMMs, current sources, and ammeters. The card and KHETS software take advantage of the built-in DMM in the 3706A so that an external voltmeter is not required for measurements.

The Keithley 3765 is a signal conditioning card designed to buffer test signals from the Hall sample to the measurement instrumentation and to switch current from a source to the Hall sample. When used with Keithley’s 3706A mainframe, the 3765 provides the switching capability to measure Hall voltages as low as 50 nV and sample resistances in excess of 1012 Ω.

All accessories needed to connect the sample holder, scanner, instruments, and controller are included, greatly simplifying connections and reducing setup time. The 3765 is connected directly to the sample, and all instruments are connected via GPIB to the controller.

The Keithley 3765 can be operated in either low resistivity or high resistivity mode. In the high resistivity mode, input impedance is greater than 100 TΩ, input bias current is less than 50 fA, and output resistance is 10 kΩ. Input voltage ranges in both operating modes is -8 V to +8 V. If higher voltage is desired, Keithley recommends using a 6221/6517B system. Cabling and sample connections must be carefully designed to make full use of the capabilities of the 3765. Refer to Keithley’s Low Level Measurements handbook for guidance in designing these connections.