1.5 A fast-blow — what the ratings mean for fit
The 045101.5MR: Rated 1.5 A continuous at both 125 V AC and 125 V DC — the same voltage ceiling on both sides means it handles AC or DC rails without derating the voltage spec. Fast-blow response time: the fuse element opens quickly on overcurrent, protecting sensitive semiconductor loads where a time-delay fuse would let the fault energy pass through. Breaking capacity of 50 A at rated voltage — this is the maximum fault current the fuse can safely interrupt without rupturing. For a 1.5 A rail, 50 A interrupting rating covers most secondary-side faults in low-power supplies.
Melting I²t and cold resistance
Melting I²t of 0.853 A²s — this is the energy needed to melt the fuse element. It tells you whether the fuse holds through inrush from a capacitive input filter or a motor start. For a 1.5 A fast-blow, 0.853 is low; expect it to open on moderate inrush unless the pulse energy stays well below that threshold.
SMD footprint and approvals
2-SMD square end block package, surface-mount — the 0.240" x 0.106" x 0.106" footprint is common for NANO² fuses and fits standard pick-and-place reflow assembly. Approved by CSA, PSE, and UL — these agency marks cover North American and Japanese safety standards, so the fuse is accepted in equipment sold into those markets without additional component-level certification.