Fast-blow 250 mA fuse for secondary-side protection
The F1206A0R25FWTR is a 250 mA fast-blow surface-mount fuse from the KYOCERA AVX Accu-Guard® series, rated for 32 V DC with a breaking capacity of 50 A at rated voltage. With a cold resistance of 0.75 Ω, the voltage drop at rated current is roughly 188 mV — negligible in a 24 V or 12 V rail, but worth accounting for in a 3.3 V or 5 V low-voltage branch where the fuse adds about 5–6 % of the rail voltage.
Melting I²t and inrush handling
The melting I²t of 4E-05 A²s sets the energy threshold for the fuse element to open — useful for sizing against capacitor inrush or brief overcurrent events. The fuse's I²t of 4E-05 A²s at 32 V corresponds to an energy threshold that a direct short on a charged capacitor could exceed.