Hello,

I'm preparing for a test this Wednesday and I'm stuck on this exercise:


Vd1 = voltage across D1
Vd2 = voltage across D2
e = in voltage
s = out voltage

I need to study 4 cases:

• D1 is not blocked, D2 is blocked
• D1 is blocked, D2 is not blocked
• Both are blocked
• Neither are blocked

As you can see I started with D1 is not blocked, D2 is blocked, but I have no idea where to start. I tried representing D1 and D2 accordingly (Vt = 0.6V), but what should I do next? Thank you in advance for your help.

 

You analyze the circuit and determine the voltage across each open (blocked) diode and the current through each closed (not blocked) diode. You then check if these conditions are possible.

 

You analyze the circuit and determine the voltage across each open (blocked) diode and the current through each closed (not blocked) diode. You then check if these conditions are possible.

Are the 2 schematics I made for case 1 correct? And if yes, is it ok for me to just say that s is e - (E1 + Vt)?

 

Are the 2 schematics I made for case 1 correct? And if yes, is it ok for me to just say that s is e - (E1 + Vt)?

It looks like you are going okay. Is 's' the voltage across the resistor?

 

It looks like you are going okay. Is 's' the voltage across the resistor?

Sorry for the late reply, but I was in school. s is the voltage across the resistor, which also is the output voltage.

 

Did the first case. Is this correct?

 

What have you done to check the validity of your own answers? That is a critical skill that you need to be developing now, not at some ill-defined point in the future.

 

Of course. In the example we had in class (which was a bit easier), the inconsistencies were obvious during the procedure but I didn't find any inconsistencies with my systems, so I'm not really sure how to check.