I'm given a strange single-diode circuit where you must find out whether or not the diode is on. See the top diagram in the linked image: http://i.imgur.com/y1sn3.png (Current source is indeed 1 Amp, not 1mA as the 2kΩ resistor would suggest. Please do not try to correct the initial question by flipping the diode or whatnot. I have confirmed that this is exactly the question that must be solved.) So to solve this, I tried examining the circuit as if the diode were open. I stuck a ground at the positive end of the voltage source for reference (I know it's a weird location but for simple circuit analysis it should be arbitrary, right?) and then looked at the voltage from that point to the positive end of Vd to get Va. I started again at ground, but this time went towards the negative terminal to get Vb. I used the voltage difference principle 'V=Va - Vb` to see if the voltage across the gap was greater than 0.7V. It was not. After asking a few people they say I have a sign error but I cannot find it. Thanks for the help!