Question
a) Figure 1 shows a full wave rectifier. Sketch the output voltage, v(t) with the labels of peak voltage and period. Assume all the diodes in the circuit are ideal.

b) Repeat part a if the diodes D3 and D4 are replaced by R3 and R4 respectively.

c) Repeat part a if the circuit shown in figure 2 is used. Assume the offset model is used for the diode with the offset voltage of 0.7V.


figure 1

figure 2

 

Hi.
Your images don't work.

 

Which diodes will be forward biased during the positive half cycles of the input wave?
Which diodes will be forward biased during the negative half cycles of the input wave?
Reference:
http://www.allaboutcircuits.com/vol_3/chpt_3/4.html
http://raise.spd.louisville.edu/ECE252/L17.htm

 

Question
a) Figure 1 shows a full wave rectifier. Sketch the output voltage, v(t) with the labels of peak voltage and period. Assume all the diodes in the circuit are ideal.

b) Repeat part a if the diodes D3 and D4 are replaced by R3 and R4 respectively.

c) Repeat part a if the circuit shown in figure 2 is used. Assume the offset model is used for the diode with the offset voltage of 0.7V.


figure 1

figure 2

OK, after re reading, I think I understood what I have to answer.

To whom should I sent my work?

Is it just a quiz? Any prize for the winner?

 

i have done part a and c.
but i am not sure correct or not.
can you send me your work or i upload my work here？

 

am i right？？
https://www.dropbox.com/s/479fyoykn3ec77g/PhotoGrid_1398865805835.jpg

 

I am going to upload your answer here.

First, for part c, I think you are not completely right.
What is the output voltage as the input voltage is positive but less than 2*0.7 = 1.4V?
( 0< Vin < 1.4V)
Why Vout = 0 for the half cycle?
This is full wave rectifier and therefore, Vout should not be zero there.
For part b, your answer is not correct.
How do you calculate the output voltage?
Could you upload your work with details on how you get that result?

 

Anhnha
Why 1.4V in part C ?? And positive voltage ?

 

Anhnha
Why 1.4V in part C ?? And positive voltage ?

I was referring to the positive half cycle. However, the same goes for negative half cycle.
For 1.4V, I think as Vin is less than the total drop voltage of two diodes, Vout will be zero.
Am I right?

 

I was referring to the positive half cycle. However, the same goes for negative half cycle.
For 1.4V, I think as Vin is less than the total drop voltage of two diodes, Vout will be zero.
Am I right?

But in part C we use this circuit

 

Well, sorry for the mistake. I misread the question!
So, manking's answer is not completely correct.
For -0.7V < Vin < 0V, Vout should be zero.
manking:
Could you show the input waveform along with your answer? This will make it easier to see if you are right or not.

 

https://www.dropbox.com/s/avutd0hweiwc54o/circuit_07.jpg
https://www.dropbox.com/s/pc5g3og46qs09ux/circuit_08.jpg
thats my friend told me how to do this. actually i cannot get the idea.
any mistake in part a and c？

 

what should i sketch for part c.for 0V in first half period and 9.3V in the other period or exchange the position？？

 

b) Repeat part a if the diodes D3 and D4 are replaced by R3 and R4 respectively.

Please see the equivalent circuit with diodes D3 and D4 replaced by R3 and R4 respectively.

Now for the positive half cycle:

1. Are diodes forward biased or reverse biased?
2. What are voltage drops across these diodes?
3. Can you calculate Vo now?

Now for the negative half cycle:

1. Are diodes forward biased or reverse biased?
2. If the diodes are reverse biased, remove them from the circuit.
3. Can you calculate Vo now?

 

what should i sketch for part c.for 0V in first half period and 9.3V in the other period or exchange the position？？

Please look at this.

For the negative half cycle:
With -0.7 <Vi< 0, diode is OFF and Vo = 0.
With Vin< -0.7V, diode is ON and the voltage drop across diode is 0.7V.
Can you calculate Vo?

For the positive cycle, diode is OFF.
What is Vo?

 

may i do it in this way?

 

may i do it in this way?

Yes, there is no different.

 

b) Repeat part a if the diodes D3 and D4 are replaced by R3 and R4 respectively.

Please see the equivalent circuit with diodes D3 and D4 replaced by R3 and R4 respectively.

Now for the positive half cycle:

1. Are diodes forward biased or reverse biased?
2. What are voltage drops across these diodes?
3. Can you calculate Vo now?

Now for the negative half cycle:

1. Are diodes forward biased or reverse biased?
2. If the diodes are reverse biased, remove them from the circuit.
3. Can you calculate Vo now?

Now for the positive half cycle:
1. Are diodes forward biased or reverse biased? F.B
2. What are voltage drops across these diodes? no voltage drop
3. Can you calculate Vo now? peak Vo is 10 like sine wave

Now for the negative half cycle:
1. Are diodes forward biased or reverse biased? R.B
2. What are voltage drops across these diodes? any voltage drop
3. Can you calculate Vo now? 0V

is it look like this??

 

You are correct about the positive half cycle. However, please answer the negative half cycle questions.

1. Are diodes forward biased or reverse biased?
2. If the diodes are reverse biased, remove them from the circuit.
3. Can you calculate Vo now?

 

You are correct about the positive half cycle. However, please answer the negative half cycle questions.

1. Are diodes forward biased or reverse biased?
2. If the diodes are reverse biased, remove them from the circuit.
3. Can you calculate Vo now?

1. they are reverse biased
2. R =R3+R6+R4=22ohm
3. I DONT KNOW HOW TO DO USING V=IR