How is the "I" current calculated in this circuit?
To find I it is a similar process and you can take credit for the fact that there is no load at Vo

Determine the voltage difference: 10V -&gt;  -2V  = 12V
remove additional voltage drop: assume diode is 0.6V: 12 - 0.6V = 11.4V
calculate current through the resistive chain:  11.4/(1200+4700) = 1.932mA