2020 Solution 01

What is the voltage measured by an ideal voltmeter at the output net out through the diode? You can assume that the nominal diode drop is VTH ~ 0.7V, or generally VTH << vbat.
(a) 9V​
​(b) 9-0.7 = 8.3V​
​(c) 0.7V​
​(d) 0.0V​
​(e) .....
Your answer
For an ideal voltmeter, the input impedance is infinite. Therefore the current in the circuit is zero. The only solution to the diode equation occurs when the drop across the diode (Vd) is zero. Therefore the voltmeter will read all of 9V.
See the associated diode or Shockley equation.
This is an easy experiment to do at home!