Is 1N4001X different than 1N4001??? I can't find it in your file!

I meant to say the 1N400X (family) where X is a number from 1 to 7. Sorry for the confusion.

 

Ok... No problema... Back to fight...

So, a diode, directly polarized only lets the current flow when the potencial diference between anode and cathode is between 0.6 and 0.7v, right?

So, what should i understand by "characteristic curve"? I have a report to my Electronics class and the teacher asks for that?

Should i show him the Vd or the Id??? Or what curve is this?

I have made a simulation usin DC Sweep with this setup:

.dc V1 0.1 1.5 0.1

Is it good enough to get an overall idea of a diode behaviour?

 

hi,
This plot is from the 1N4001 datasheet.

Note: the Vfwd/I relationship is not linear.

E

 

Is the Vfwd/I the "characteristic curve"?

With that setup i got what i added as attachment.

How do i do a relationship between 2 measures in LTSpice?

 

Is the Vfwd/I the "characteristic curve"?

hi,
Yes.

How do i do a relationship between 2 measures in LTSpice?

Not sure what you mean.?
If you mean create a new plot from two parameters.

Right click on the plot area, from the drop down menu select 'Add Trace' and then type the required plot equation in the lower box. [ Use the Data that show in the window of the 'Add Traces to Plot'

E

 

Ok, i got that too! Thanks...

Now they ask me to replace the DC Voltage source to an AC voltage source. They want a sin entry signal, with 5V of magnitude and a frequency of 1KHz.

What type of simulation should i run? transiente?

 

hi,
You could use a Transient Response plot.
Have they they said what frequency and amplitude you must use for the simulation source.?

 

Yes, i wrote it in the previous post...

Sin, 5V, 1KHz.

But I'm struggling to understand which data should show up in X-axis and Y-axis... They first ask for a temporal graphic for Vout with 5V magnitude and 1KHz and then change the magnitude to 10V. Then they ask if i can get the caracheteristic curve from those 2 simulations, and if so, then I should plot it...

So i might need here maybe 4 graphics if i understood it. 2 graphics for temporal graphic for 5 and 10 V of magnitude. Then the other 2 should be the caracheteristic curve for 5V and 10V, but i'm not sure!

 

But I'm struggling to understand which data should show up in X-axis and Y-axis

Its usual to have the Voltage as the Xaxis and the Current on the Yaxis [Logarithmic] as per this example.

To change the LTSpice plot in the Yaxis, place your cursor on a value on the Yaxis scale markings, mouse left click and then check the 'Logarithmic box] .

As this is homework please post back what you think are the answers to the questions being asked.

E.

 

Well, I think i got it. At least for the 1st question.

They wanted a plot of Id(Vd) which means in the y-axis will come the Id and the X-axis will come the Vd...

I did that and got what i have in the attatched file.

The Simulation command was:

.dc dec V1 0 2 20

And the circuit we are analysing, has a resistor between the Voltage Source and the Diode of 220 ohms...

 

Now, for the next question, they want the same but with an AC voltage source like I said before.

Sin, 5V magnitude and 1KHz...

But then, when i try to do the same as before, my plot gets really weird...

The 1st plot is acceptable, though there is a slight glitch that i do't understand. But the 2nd plot is really weird!

 

The second plot is normal. It shows that the diode doesn't start to conduct until its forward voltage reaches about 0.65V, as would be expected. Why do you think it's weird?

Edit: What "slight glitch" are you referring to?

 

The second plot looks like weird to me because of the line that splits into 2 and the they reunite again... Is that normal in the plot?

The slight glitch is at about 0.45ms, then again at about 1.5ms and last at about 2.5ms, when the red curve is going down, at the bottom...

 

The second plot looks like weird to me because of the line that splits into 2 and the they reunite again... Is that normal in the plot?

Please post your *.asc file for the latest plot you have posted.

 

There it is!

I have assigned the Diode Voltage to X-axis and the green line is the Diode current, i guess that was the order I've choosen!

 

hi,
With your *.asc file I get this plot, ref image.

Would you post the exact question being asked by your tutor, as its possible to simulate a number of different diode parameters.

Which parameters do you want to plot.?

E

 

I want to plot the same as before (carachteristic curve I(Vd)) but with a sinusoidal entry voltage and i got the plot i sent before...

Your plots are entry voltage, diode current and diode voltage based on time. I need to plot the diode current based on the diode voltage.

Hope i have explained my self clear or hope i made myself clear. Better english this way!

 

hi,
Do you mean like this, ref image.

For the previous image I posted , I did use your asc file.

I cannot see why you want to plot the diodes I/V, at 5Vppk , 1KHz in the time domain.??

E

 

That second curve i get in my simulation have disapeared because you used a different Simulation Command which i don't know if i should do it.

Somehow, that second curve i get is not showing up with the simulation command you used! Probably that Simulation command keeps it out of plot range.

 

Its not shown because of the shorter plot period.

I have extended the plot period.
The long trace is the I/V on the rising quadrant half cycle of the 1KHz and the shorter trace is for the falling quadrant of the half cycle.

The offset could be due to a diode characteristic, say carrier storage in the diode, diode capacitance, etc,, or a possible artifact of the simulation

E


EDIT:
Added 2nd image.