Show your analysis so we can see where you're getting confused.

 

Hello, which part are you facing problems with?

 

You calculate the voltages for the inputs in their stated states, which seems straight-forward.
What difficulty are you having with that?
Have you not studied Ohm's law and basic circuit analysis?

 

Assume one of the inputs V0 or V1 is at ground because that is what is required to make the output low.

How many diodes between V01 and ground? How many between V02 and ground? Does this help you calculate the two voltages?

 

I can only write KVL equations and stuck here: @dl324 , @crugorocks , @crutschow , @BobTPH

 

Why did you not include V1 and V2 in your KVL equations to solve for the node voltages?

Use the value of V1 and V2 to solve for Vo1.
Then solve for Vo2

 

I can only write KVL equations and stuck here

Why are you bothering with KVL? V1=V2=5V, what is the voltage at V01? Then solve for V02.

 

Why are you bothering with KVL? V1=V2=5V, what is the voltage at V01? Then solve for V02.

I write 2 KVL equations to solve V01, @crutschow

 

Seems to be a trick question. As per schematic conventions, The right side 10 K and D4 play no role whatsoever.

 

I write 2 KVL equations to solve V01, @crutschow
View attachment 349603

Your equation is wrong. With V1=V2=5V, what is the current in D1/D2 and R?

Why are you using 0.7V for the diode voltage drop when the instructions state it's 0.6V?

 

Your equation is wrong. With V1=V2=5V, what is the current in D1/D2 and R?

Why are you using 0.7V for the diode voltage drop when the instructions state it's 0.6V?

Do

Your equation is wrong. With V1=V2=5V, what is the current in D1/D2 and R?

Why are you using 0.7V for the diode voltage drop when the instructions state it's 0.6V?

Your equation is wrong. With V1=V2=5V, what is the current in D1/D2 and R? I cannot solve your answer. I don't know.

 

The right side 10 K and D4 play no role whatsoever.

They do if V1 and V2 are high.

 

I cannot solve your answer. I don't know.

If the diode is not forward biased, what is its voltage drop?

Hint. You weren't given reverse leakage information for the diode, so I'd assume ideal characteristics for this condition.

 

If the diode is not forward biased, what is its voltage drop?

Hint. You weren't given reverse leakage information for the diode, so I'd assume ideal characteristics for this condition.

that is correct, all diodes are ideal because these are practice problems.
V1, V2 make D1, D2 reverse bias, at D1, D2 open circuit, right?

 

that is correct, all diodes are ideal because these are practice problems.

They're not ideal because the forward voltage drop isn't 0V.

V1, V2 make D1, D2 reverse bias, at D1, D2 open circuit, right?

Or a very high resistance so you still have a loop for KVL.

 

sigh...

obviously someone needs serious help. the circuit is two separate AND gates.

KVL ass applied in initial post is wrong. it assumes Vf=0.7V even before determining if there is a current through D1 or not.
then results get out of proportion. one should always check if there are any storage elements in the circuit (capacitor or inductor) or additional sources, and if levels are observed at steady state or not. if no storage elements or additional sources, then voltage levels can ONLY be within shown supply limits (0V and 5V). any result outside that range is supposed to be IMMEDIATE red flag.
in other words -0.7V and 5.7V values are a clear signs of wrong analysis.

next one need to observe and analyse individual circuit (gate), not the entire thing. And this better be generic... so it can be applied to the next gate.

 

They're not ideal because the forward voltage drop isn't 0V.

Or a very high resistance so you still have a loop for KVL.

yeah, still have a loop for KVL, right?

 

in digital world, signals are true or false ( logic 0 / logic 1)
range for levels are defined for each logic family and they are NOT fixed...

so

generic case would be to describe what happens when V1 is at one of the logic levels. simple way to ignore the other input is to connect all inputs together ( V1 =V2).
If V1 is 0V, output Vo1 is _____
If V1 is 5V, output Vo1 is _____
If V1 is undefined (such as 1.785194V), the output Vo1 is ______

this is short and simple and this is what is needed to analyze entire circuit (which could have MANY gatees)

 

When V1=V2=5V diodes D1, D2 are:
a) reverse biased
b) forward biased
c) ....