led lamp circuitry that emulates an incandescent lamp &# 39 ; s behavior upon remote verification of the led lamp . the led lamp circuitry presents an input power switch circuit , a fuse blow - out circuit and a cold filament detection circuit permitting the use of led lamps in applications , such as railway signal light applications , where there is a need for remote monitoring of the lamps , while keeping the advantageous features of lower power consumption and longer life .