- #36
NTL2009
- 596
- 380
Agreed. And the earlier discussion of a 'perfect 12V battery' applied to a 'perfect 0.3V Vf diode' isn't a useful real-world model. It's the same as a 'perfect battery' connected to a 'perfect conductor', or the theoretical infinite force applied to an infinite mass. It is undefined. One or the other has to 'give'.CWatters said:A lot comes down to which model of a diode you are using. The problem statement provides very little information so you have to assume a very crude model, almost an ideal diode but with a defined forward voltage.
So either we assume enough internal resistance in the battery so that the diode will clamp the battery terminal's voltage to 0.3V w/o burning up, or we assume the battery can maintain 12 V, and the diode burns out, or somehow the diode can survive with 12V forward voltage (I don't think any real diode can - if you extrapolate the I/V curve I think you will soon reach mega-amps!)