I was using a 12V 1A wall wart yesterday to power a project when I heard so mething in it go "pop". My project draws approximately 0.5A. Postmortem rev ealed a dead resistor on the 120V input to the wall wart, which appears to be a 1 ohm 1/2 watt resistor. The wallwart is a swithmode power supply.1) Am I correct in assuming this 1 ohm resistor was some attempt to save mo ney on a fuse? or does it actually serve some purpose other than as an easy point of failure?
2) Is there a way to compute how much power was being dissipated across the resistor? I suppose I could replace it and measure the voltage drop across it?3) Was it a bad resistor that popped, or a bad wall wart design? or both?