Fig. 1. Volt-ampere characteristic curve of the probe operation

Fig. 2. Probe diagnostic circuit and structure

Fig. 3. Configuration of the probe diagnostics

Fig. 4. Probe control loop

Fig. 5. Test main controller

Fig. 6. Test platform

Fig. 7. Probe test overall waveform

Fig. 8. Local magnification of probe current

Fig. 9. Arc images at 0~0.9 ms before current crosses zero

Fig. 10. Electron density curves at different switching current

Fig. 11. Electron density curves under different types of contacts

Fig. 12. Comparative verification test