sentences:  Curve tracers, especially high-current models, are usually supplied with various semiconductor device test fixture adapters that have Kelvin sensing.Some analog curve tracers, especially sensitive low-current models, are equipped with a manual control for balancing a capacitive Bridge circuit for compensating ("nulling") the stray capacitances of the test setup.This adjustment is performed by tracing the curve of the empty test setup (with all required cables, probes, adapters and other auxiliary devices connected, but without the DUT) and adjusting the balance control until the I curve is displayed at a constant zero level.