Keithley 3145 CableErrorsArticle free download

File name 3145_CableErrorsArticle.pdf

A G R E AT E R M E AS U R E O F CO N F I D E N C E leads caused by high currents, excessive lead resistance can still create measurement prob- lems. When testing an LED using pulsed rather than DC currents, fast rise and settle times are critical to obtaining the shortest pulse widths to minimize device self-heating. Minimizing lead resistance makes it possible to obtain the fastest rise times. Minimizing cable inductance is also crucial when testing LEDs with high test Minimizing Cable-Induced currents. Essentially, inductance resists changes in current by creating a voltage drop when the test current is changing. Although Measurement Errors in inductance in the test leads will have no effect at the top and bottom of the pulse, where the current is constant, it will cause High Current Applications an additional voltage drop during the rising and falling edges for which the SMU must compensate. As with resistance, minimizing lead inductance is important for obtaining the fastest rise time. Dave Wyban