# I am Stuck on this question, this is the last and more difficult. I need to deliver tomorrow

#### lsdjunio

Joined Nov 20, 2020
10
6. Consider the circuit in the following figure with the following characteristics:
• The input voltage waveform is sinusoidal with a peak voltage (amplitude) of 30 V and a frequency of 50 Hz;
• R1 = 500 Ω; R2 = 1 kΩ;
• Diode D1 and diode D2 have the same characteristics: Vd1 = Vd2 = 0.8 V and Rd1 = Rd2 = 100 Ω.

6.1. Indicate to which VIN values diode D1 leads to.
6.2. Indicate to which VIN values diode D2 leads to.

Last edited:

#### ericgibbs

Joined Jan 29, 2010
11,577
hi I,
Welcome to AAC.
E

#### WBahn

Joined Mar 31, 2012
26,398
You need to show YOUR best attempt to work YOUR homework. That is the starting point that we can use to help you get past the specific point that is causing your problems so that you can proceed.

#### dl324

Joined Mar 30, 2015
12,224
Welcome to AAC!

What does "leads" mean in this context? There are no capacitors or inductances that would cause leading or lagging.

#### lsdjunio

Joined Nov 20, 2020
10
hi I,
Welcome to AAC.
E
I really try, but i just stay stuck in the question cause idk what i need to do. I can show u the past 5 exercises solved by me. I just dont know what i need to do for the question.

#### lsdjunio

Joined Nov 20, 2020
10

#### lsdjunio

Joined Nov 20, 2020
10
Welcome to AAC!

What does "leads" mean in this context? There are no capacitors or inductances that would cause leading or lagging.
Now it's fixed, sorry.

#### WBahn

Joined Mar 31, 2012
26,398
Here:

6.1. Indicate to which VIN values diode D1 leads to.
6.2. Indicate to which VIN values diode D2 leads to.
This is just a language barrier issue. Please explain what it means.

#### lsdjunio

Joined Nov 20, 2020
10
Here:

This is just a language barrier issue. Please explain what it means.
Now it's fixed. Sorry

#### WBahn

Joined Mar 31, 2012
26,398
I really try, but i just stay stuck in the question cause idk what i need to do. I can show u the past 5 exercises solved by me. I just dont know what i need to do for the question.
That won't work. You may be completely above board, but how do we know that the past five exercises weren't "solved" by telling other folks that you just need help on that one and, after someone here solves this one for you, that you won't go somewhere else and offer to show them the past 6 exercises solved by you, so could they just please help you with the 7th?

But that's beside the point. If you've really been working on this so hard, you should have SOMETHING to show for it, no matter how bad it might be. Show what you've got so that we have something to work with. If you are SO lost that you've sat there for hours and have come up with not one notion of how to start, then the best thing for you is to take the zero on this problem so that your instructor can see where you are deficient so that they can help you get caught up. Otherwise you will just be digging your hole deeper and deeper.

Joined Feb 20, 2016
3,657
Maybe it means to show the waveform across the load (R2) and indicate what part of the waveform is produced by the action of D1 and then D2?
Try a few steps. Draw the wave shapes you expect.
Work out what is going on with just R1 and R2 in circuit.
Then, add D1, so it is R1, R2 and D1.
Then again, without D1 but with D2,
Finally with both diodes.

#### WBahn

Joined Mar 31, 2012
26,398
Now it's fixed. Sorry
Fixed where? I still see the same thing in your original post.

I see a blank post (a post with a single period). Are you sure you attached the fixed image?

#### lsdjunio

Joined Nov 20, 2020
10
Maybe it means to show the waveform across the load (R2) and indicate what part of the waveform is produced by the action of D1 and then D2?
Try a few steps. Draw the wave shapes you expect.
Work out what is going on with just R1 and R2 in circuit.
Then, add D1, so it is R1, R2 and D1.
Then again, without D1 but with D2,
Finally with both diodes.
Just with R1 and R2= 0.014 A
R1,R2,D1 = 0.031 A
R1,R2,D2 = 0.031 A
R1,R2,D1,D2 = 0.041 A

Joined Feb 20, 2016
3,657
Maybe, but it is AC. Draw the waveforms over a full cycle to understand a bit better.
Start with the voltage across R2. Then you could go to the current from the supply. That will be a bit more complicated.
If you do it in steps like above, that will help you.

#### djsfantasi

Joined Apr 11, 2010
7,210
Now it's fixed. Sorry
Do you mean you found a solution? Post it and we can double check your work

#### lsdjunio

Joined Nov 20, 2020
10
Maybe, but it is AC. Draw the waveforms over a full cycle to understand a bit better.
Start with the voltage across R2. Then you could go to the current from the supply. That will be a bit more complicated.
If you do it in steps like above, that will help you.
v(t)=30.sin(2 π . 50 t)
I can use any number to T?

#### lsdjunio

Joined Nov 20, 2020
10
Do you mean you found a solution? Post it and we can double check your work

#### WBahn

Joined Mar 31, 2012
26,398
That is still very hard to understand what is being asked.

My best guess is that you are expected to draw the input and output voltage waveforms over a complete cycle and indicate what parts of the cycle the two diodes are on and/or off during.

#### lsdjunio

Joined Nov 20, 2020
10
I will try, and after that i will put right here what i did, wait an answer from me please

#### MrAl

Joined Jun 17, 2014
7,879
All you have to do is figure out what input voltage causes each diode to conduct.
It looks like you have 0.8v diode drop with 100 ohms in series so you have to set the circuit up like that. You can do one half cycle at a time.

My guess is that you have to find the Vin that causes each diode to conduct, then calculate the output voltage at the peak of each input half cycle.

It would help if you understood the principle of superposition.