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Need simulation results of circuit ...

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anas.ansarie

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I need to simulate this circuit and find its frequency behavior (upto which frequency it can be operated) and the transient analysis ... somebody please help me ... as i dont have much time ... Untitled.png

I build this on LT spice .... if anyone knows how to do simulation in LTspice .. please tell me ... i mean i dont know much about LTspice ....

Thanks
Anas
 

I know ltspice send the asc file.. checkout d1 position and tell us what u trying to do.
 

Thanks View attachment Circuit.zip




i want to give a square wave at the base of Q1 (the first transistor) and check the output at capacitor C6 (right most) ... just to find till how much frequency this circuit can be operated .... i mean at what range of MHz the circuit has its 3dB frequency ...
 

just ignore D1 and the resistor ... think like transistor is being switched on and off by a square wave
 

ne592 cant find it on ltspice directory ..says " cant simulate ne..." circuit opens ok
cant help without value of ac1 and pulse wave freq /voltage need more info.
where did u get the ne model ?
 

sorry i just noticed and i was about to give you the library files of this NE592

this is the link you will find it here or i'll put it here in a minute
 
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View attachment lib.zip


1. these are the library files for NE592

2. the voltage of AC1 may be 0.7 V ( just to switch on the transistor)

3. the frequency from 10 Khz first then 10 Mhz last ...

i would be really thankful to you if you provide me just the frequency response of the circuit ... (neglecting D1 and the resistor
R2)
 
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Ok i applied 12vdc supply with 5v ac (AS AC1)
THEN 100khz-10mhz pulse adding ac2 at base of transistor thru 47k resistor and got the circuit working..now what ?
 
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Hmm, I thought I recognised that circuit! If you want to know the frequency response you had better draw it correctly first. As it is, it doesn't make sense and so probably won't do what you want.

Also, an AC analysis would be used to normally find the frequency response of a circuit but that is a small signal analysis. You are talking about a square wave input so it cannot be done that way. You could step the input frequency in a transient analysis.

Rather than getting someone else to do the simulation it would be better to learn how to learn to use the tools you have. I believe LTspice has a decent help system. Hit F1 or select 'help' from the menu and look up how to do an AC or transient analysis.

One problem (other than what I assume are drawing errors rather than 'design changes') is that you have an AC source for the power supply. That should be a DC source and you need an AC source for the input signal. However, that would not work as the circuit stands answer there is no bias to the input transistor (which I assume would be a phototransistor). It would probably make sense to bypass the first transistor and put an AC source to the collector.

Keith
 

Hello Keith...
U are right about some people asking "too much " but here i think he is trying to design a complicated circuit and for that i give him credit ,knowing that some times i get to learn too, in this case i got to understand from him how to work with "these are the library files for NE592 " "http://www.g-pb.de/LTspice/ " (as these .asy & .sub files r not in the basic ltspice lib)things i did not quite know/understand before as i am also new with ltspice .
 

To understand about the necessary corrections to the circuit, it would be a good idea to consult the NE592 datasheet. You'll notice, that G1A/G1B must not be shorted to V- rather than bypassed with a capacitor.
 

Keith is right in that you need to have a dc power supply attached to the circuit if you don't intend on running an operating point (dc) analysis. Any spice will run an operating analysis first to determine the equilibrium voltages and currents in order to determine the ac equivalent circuit parameters for the devices (diodes, transistors, etc.). Therefore, you need to connect the ac source where the input signal would be injected. Also, I don't think LTspice will like the floating capacitor C6 (2.2nF) at the far right of the circuit.

If you are going to be looking at a response to a square wave, that would be considered a large signal analysis and I think you would be better of with running transient analysis where you vary the frequency of the input source. However, to do this you must run a separate transient (.tran) analysis for each frequency of interest.

v_c
 

dselec said:
Ok i applied 12vdc supply with 5v ac (AS AC1)
THEN 100khz-10mhz pulse adding ac2 at base of transistor thru 47k resistor and got the circuit working..now what ?
Click to expand...

Thanks ....

Actually that was my mistake ... i didnt provide any supply voltage (Vcc) ... my bad ...

anywayx ... can you give me the result of its transient analysis

or if you give me the modified .asc file too ... that would be helpful ...

Thanks

---------- Post added at 15:01 ---------- Previous post was at 14:57 ----------
keith1200rs said:
Hmm, I thought I recognised that circuit! If you want to know the frequency response you had better draw it correctly first. As it is, it doesn't make sense and so probably won't do what you want.

Also, an AC analysis would be used to normally find the frequency response of a circuit but that is a small signal analysis. You are talking about a square wave input so it cannot be done that way. You could step the input frequency in a transient analysis.

Rather than getting someone else to do the simulation it would be better to learn how to learn to use the tools you have. I believe LTspice has a decent help system. Hit F1 or select 'help' from the menu and look up how to do an AC or transient analysis.

One problem (other than what I assume are drawing errors rather than 'design changes') is that you have an AC source for the power supply. That should be a DC source and you need an AC source for the input signal. However, that would not work as the circuit stands answer there is no bias to the input transistor (which I assume would be a phototransistor). It would probably make sense to bypass the first transistor and put an AC source to the collector.

Keith
Click to expand...

Yeah Keith ... you are right ... i realized my mistake when i posted here ... :) n m feeling really bad about it ..... yeah i tried to study its guide but due to less time i left ..... regarding the circuit ... i used those components which were available to me right now ... Anywayx Keith ... will surely keep in mind your advice :) Thanks
 

You do need to fix the drawing errors for the simulations to be useful. For example the original circuit had a long tailed pair output stage (i.e. emitters connected) - you haven't. In fact the emitter of the output transistor is connected to ground.

Keith
 

You do need to fix the drawing errors for the simulations to be useful. For example the original circuit had a long tailed pair output stage (i.e. emitters connected) - you haven't.
Click to expand...
And other errors that have been previously mentioned.
 

dselec said:
Ok thanks
Now i understand where /what he is doing so since it was your post first u can point out to him his circuit errors
Click to expand...

yeah i realized ... so many mistakes .. m sorry ... :(

i tried to study its guide ... but m unable to plot the AC analysis of complete circuit ... like one (gain diagram, phase diagram)... can you help me out in this regard

---------- Post added at 20:18 ---------- Previous post was at 20:17 ----------

or if you have doone the simulation ... can you put .wmf files here ?
 

what are wmf files ?
ill send you your circuit repaired u can run and find out info ...change v2 freq (ton & t period)
 

Attachments

  • NE592a.rar
    394 bytes · Views: 122
  • ne592 video Circuit.rar
    1.2 KB · Views: 107
  • NE592.rar
    799 bytes · Views: 117

I think wmf files are simple graphics files (Windows Meta File) -- these are just "pictures" of the schematic.
They are normally exported from LTspice via the Tools menu item (Tools > Write to a .wmf file) to be inserted
into a document (for example a word processing software like MS Word).
 
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