I don't know what I'm doing wrong. Perhaps someone can explain this. Is there any reason an ammeter would cause a voltage regulator to explode?
I'm trying to understand how to use the LM317 voltage regulator with a potentiometer to reduce 12 volts to a variable voltage between 1.25 and 10.5 volts. The 12V is generated from an ATX PC power supply, and the circuit I am using can be found here: http://www.electronics-lab.com/articles/LM317/
The only difference to the above schematic is that for R1 I am using a 680 ohm resistor, and R2 would be a 5k ohm potentiometer but I haven't even gotten that far yet. After building the circuit, I connected a multimeter to the output of the circuit and shorted what would have been the potentiometer (therefore simulating 0 ohms or full open) and read 12.5 volts. It read steady for several seconds, so I switched from volts to amps on the multimeter, and POW! The LM317 was no more.
Perhaps there is something fundamental I am missing, but what would cause this? Are my calculations (using the above website as a reference) completely wrong? If so, what would I need to do to accomplish my goal of taking a 12V supply and using a potentiometer to vary the output in as wide of a range as possible? Would there be a benefit to having a fuse (perhaps 1 amp) on the input voltage?