A Hall A Hall sensor is a 4-lead device. The control current (IC) leads are normally attached to a current source such as the Lake Shore Model 121. The Model 121 provides several fixed current values compatible with carious Hall sensors.
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Caution: Do not exceed the maximum continuous control current given in the specifications.
The Hall voltage leads may be connected directly to a readout instrument, such as a high impedance voltmeter, or can be attached to electronic circuitry for amplification or conditioning. Device signal levels will be in the range of microvolts to hundreds of millivolts.
The Hall sensor input is not isolated from its output. In fact, impedance levels on the order of the input resistance are all that generally exist between the two ports. To prevent erroneous current paths, which can cause large error voltages, the current supply must be isolated from the output display or the down stream electronics.