Fuse-blow indicator
8 parts
The indicator LED sits ACROSS the fuse, so while the fuse is intact both LED terminals ride the same 12 V rail and it stays dark — measured 0.000 mA. At t = 10 ms a timed switch drops a 10 Ω fault onto the rail; the fuse current spikes to 0.53 A, past its 0.5 A rating, and the fuse latches open at 10.002 ms — one solver step after the fault, because this fuse is an instant current-blow latch, not a thermal element. From then on the supply reaches the collapsed rail only through the LED + 2.2 kΩ branch: the indicator climbs to 4.1 mA (clearly lit on the perceptual curve) as the load capacitor bleeds the rail down from 12 V to 0.04 V. The fuse is a current-blow latch — it opens the instant |I| exceeds the rating, with no i²t melting time modelled, and stays blown for the rest of the run.
- V1 12V
- LED1
- R1 2.2kΩ
- FUSE1 500mA
- C1 470µF
- R2 100Ω
- TDSW1 10ms
- R3 10Ω
