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Inrush current/Switch-ON surge is the maximal instantaneous input current drawn by an electrical device when first turned on. Inrush current is much higher than the load’s steady-state current and that’s the source of many problems such as fuse blowing up, load failure, load’s lifetime reduction, sparks at the switch contacts … etc. The figure below shows the inrush current phenomenon captured on the Siglent SDS1104X-E oscilloscope. The long spike is clear. In this article/video, I tried to address this problem with an easy, however an effective solution. I have introduced two circuits for both AC and DC loads.”

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