Design a clipper circuit with a specific output

[Hassan Raafat]

Homework Statement

Homework Equations

Clippers equations

The Attempt at a Solution

I knew that we will put a two diodes( with a dc battery {2.3 V} series) parallel to each other in opposite directions .. but what meant by gain is 0.95 ?

 

[berkeman]

Homework Statement

View attachment 97926

Homework Equations

Clippers equations

The Attempt at a Solution

I knew that we will put a two diodes( with a dc battery {2.3 V} series) parallel to each other in opposite directions .. but what meant by gain is 0.95 ?

It means that the voltage divider that you form with your series resistor and the load resistor should not drop more than 5% of the input voltage when the diodes are not conducting. Can you show us your solution circuit now?

 

[Hassan Raafat]

 

[Hassan Raafat]

http://blob:https%3A//www.physicsforums.com/e4a89897-2c3c-46b3-8433-735549d386cb

 

[berkeman]

View attachment 97936

Good! Now you just have to calculate the input resistor value so that the output voltage is 0.95 * Vin...

 

[Hassan Raafat]

Camera is not good , I can't upload complete solution but R has a value R=52.63

 

[berkeman]

but R has a value R=52.63

Can you show your equations that you used to calculate this value? It looks about right, but it would be good to see how you got it. Just type it in here... Thanks.

 

[Hassan Raafat]

http://20160325_192231.png

 

[Hassan Raafat]

http://20160325_192231.png

 

[berkeman]

Yeah, the pictures are not showing up. Can you just type it with text into the forum window?

 

[Hassan Raafat]

Vout = ( 1k / (1k+R) ) * Vin
Vout / Vin = 1k / (1k+R)
0.95 = 1000 / (1000+R)
R = 52.63 ohm

 

[berkeman]

Vout = ( 1k / (1k+R) ) * Vin
Vout / Vin = 1k / (1k+R)
0.95 = 1000 / (1000+R)
R = 52.63 ohm

Great!

 

[Hassan Raafat]

Thanks a lot , Berkeman ... You are great :)

 

[Hassan Raafat]

but I still have a question what is the waveform of input voltage ?

 

[berkeman]

but I still have a question what is the waveform of input voltage ?

Oh, that wasn't part of what you posted in Post #1. The output waveform will just be a clipped version (and 95% of) the input waveform. What kind of input waveform are you supposed to use? Sine wave? Ramp?

 

[Hassan Raafat]

sine wave

 

[berkeman]

sine wave

Of what amplitude? You should be able to draw the input and output waveforms...

 

[Hassan Raafat]

that means that the output will be a sine wave with a peak equals (100/95) * 3 , right ?

 

[berkeman]

that means that the output will be a sine wave with a peak equals (100/95) * 3 , right ?

Not exactly. The gain Vo/Vi = 0.95, and the Vo waveform clips at +/-3V.

 

[Hassan Raafat]

Not exactly. The gain Vo/Vi = 0.95, and the Vo waveform clips at +/-3V.

Am I supposed to draw input in design circuits ?

And how I determine output without knowing what is the input of circuit ?

 

[berkeman]

Am I supposed to draw input in design circuits ?

And how I determine output without knowing what is the input of circuit ?

You draw the input sine wave with some amplitude (say, +/- 5V), and then draw the output waveform which is 0.95 as big, and is clipped at +/- 3V.

One way to do it is in Excel, but you can do it by hand as well. What is the exact wording of that part of this homework problem?

 

[Hassan Raafat]

Design it meant to determine value of elements in the circuit if V,I are both known

 

[NascentOxygen]

Design it meant to determine value of elements in the circuit if V,I are both known

You don't need to know much about input V_in. If V_in at any moment exceeds the circuit's clipping level then the output waveform will be clipped, and at those times when V_in does not reach the circuit's clipping level then there will be no clipping of the waveform.

V_in can be any waveform and the clipper will still operate. It is often convenient to illustrate the operation of a clipper using a sinewave, but you could use a triangular wave, or even random noise.

Your assignment asks you to use a sinewave input. Just choose its amplitude to be whatever is needed to produce some clipping, and sketch what the corresponding output will look like.

 

[Hassan Raafat]

You don't need to know much about input V_in. If V_in at any moment exceeds the circuit's clipping level then the output waveform will be clipped, and at those times when V_in does not reach the circuit's clipping level then there will be no clipping of the waveform.

V_in can be any waveform and the clipper will still operate. It is often convenient to illustrate the operation of a clipper using a sinewave, but you could use a triangular wave, or even random noise.

Your assignment asks you to use a sinewave input. Just choose its amplitude to be whatever is needed to produce some clipping, and sketch what the corresponding output will look like.

Thanks Very much NascentOxygen , I realized that shape of wave doesn't matter .