What is the SmartFuse?

The SmartFuse is a unique, proprietary, high-speed, automatically resettable, current cut-off safety circuit. It acts to protect the Maxi-Matcher from shorted tubes, or mis-pinned insertion, or failures while testing, or over-current episodes. The SmartFuse acts within 10 milliseconds on any excursion of current beyond 120 milli-amps in the Plate circuit of the tube socket in use. It can be activated by a shorted tube. It can be activated by selecting too little grid bias, thus increasing plate current beyond the trigger point. It can be also be activated by switching values of grid or plate voltage while at higher overall current flows, due to switching transients that surpass the 120 mA hard limit.