Litmux Studio

LabPower sources and safety · 12 min

Lab: a fuse saves the wiring

A 12 V battery feeds a lamp through a 1 A fuse. You will make a short circuit on purpose (S2) and watch the fuse open the circuit before anything else is harmed - then clear the fault and replace the fuse.

The circuit for: Lab: a fuse saves the wiring
The circuit you start with

The steps

  1. Press RUN.RUN is on the toolbar (F5).
  2. Click S1: the lamp lights. It takes 5 W / 12 V = 0.42 A, well under the fuse's 1 A.A click on a switch flips it while the circuit runs.
  3. Now the fault: click S2 to short the lamp. With almost no resistance left in the loop, the current tries to rise to over 100 A - and the fuse blows within a moment. The lamp goes out and the circuit is safe.The log reports the fuse blowing.
  4. Clear the fault first - click S2 to open it - then press Reset to put in a new fuse. The lamp lights again.Replacing a fuse without removing the fault just blows the new one.

What it shows