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Instruments & Systems

Hipot Safety Testers


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Over 400 employees make up Chroma's R&D Staff.

~ from Chroma's 2009 financial report

Open / Short Check Function (OSC)

All manufacturers have faced problems with errors in test cable connection or shorts. Chroma solves this issue with its patented OSC function.

The open/short check function is used to check if the connection to the DUT is open (bad contact) or a short during the testing process. When an open contact occurs during testing, the test may result in a PASS for a product that may or should have FAILED. If there is a short in the DUT during testing, the instrument may be at risk with the high load current. Checking for opens and shorts during testing ensures efficient testing and protects the equipment.

In most cases the Device Under Test (DUT) will have some capacitance between the Input line and neutral connections with respect to AC Ground. By applying a alternating voltage and measuring the resulting current we can determine the impedance of the DUT based on its normal capacitance. If the connections are open the resulting AC current will be very low compared to the normal connection, and if the DUT is internally shorted the resulting AC Current will be much higher.