To analyze a circuit involving a forward-biased diode, you have 3 options: 1) The ideal model: treat the conducting diode as a short circuit. Very simple, but not very practical. 2) The exponential model: the most accurate description of the diode operation, but its severe nonlinearity makes it undesirable when rapid analysis is required. 3) The constant-voltage-drop model: the best of both worlds. Give the diode a fixed voltage drop of 0.7 V, and proceed with regular circuit analysis. This capt