The CDT-502 is a heavy duty, high volume, extremely accurate tester of automotive rectifiers and diodes. It is designed to provide the rebuilder with a quick, accurate and easy to test of all critical parameters associated with standard and avalanche rectifiers. The rigid industrial design and PC based user interface, make the CDT-502 a breeze to use. Extreme accuracy is achieved by real time filtering and digital processing. The tester can measure leakage as low as 10 nano-Amps. Real life conditions are simulated to maximize diagnostic capabilities. This can include a mechanical stress test. By applying compression force to the rectifier's mounting surfaces, a condition is created simulating installation of the rectifier into the alternator. Additionally, analysis of the rectifiers thermal resistance can be performed to detect poor internal diode connections and related defects. Standard diode performance tests can be performed in as little as 3 seconds for a complete rectifier. The test system can also verify the capacitors which are built into many rectifiers. The machine has programmable test profiles which include machine setup with operating instructions. It can also display pictures of the rectifier indicating diode locations. The test system also features a setup mode to configure the test conditions, tooling, and limits. Test results generated by faulty diodes will indicate their location referenced to an image of the rectifier for easy operator recognition. The CDT-502 tests the connections before the actual cycle begins. This eliminates the possibility of false test results. Faulty connections are also indicated with a graphical display for easy troubleshooting. Pass and Fail status is clearly displayed upon completion of the test cycle. Reject bin logic combined with Pass and Fail marking capabilities add to the overall performance of the system.