Pspice - HELP! 2nd order High Pass filter.

[Wicked]

Hello,

I just spent 3 hours trying to get Pspice to work! and it doesn't. =(
I am trying to make a high pass filter. The equation I am usuing is:

fc = 1/(2*pi*[(R1R2C1C2)^.5])
R1=R2 = 1.1K
C1=C2 = .1uf

fc = 1446Hz = 1.4Khz
(and I am usuing a reguar opamp on pspice to simulate this)

Can someone please help me? I just need to show the plot this on spice
to indicate this is a High pass filter and I have no idea why my
simulation isn't working. If possible please e-mail me the *.sch file
to [email protected]

Thank you very much!

 

[Ban]

Hello,

I just spent 3 hours trying to get Pspice to work! and it doesn't. =(
I am trying to make a high pass filter. The equation I am usuing is:

fc = 1/(2*pi*[(R1R2C1C2)^.5])
R1=R2 = 1.1K
C1=C2 = .1uf

fc = 1446Hz = 1.4Khz
(and I am usuing a reguar opamp on pspice to simulate this)

Can someone please help me? I just need to show the plot this on spice
to indicate this is a High pass filter and I have no idea why my
simulation isn't working. If possible please e-mail me the *.sch file
to [email protected]

Thank you very much!

If you do not show the topology of the filter, we cannot make you a
simulation file either. Since this is a critically damped 2nd order HP with
both the 0s at the origin, it could be looking like this:
___
+--------|___|-----------+
| |
|| | || |\ |
o---||----+---||-----+------|+\ |
|| || | | >---+---o
.-. +-|-/ |
| | | |/ |
| | | |
'-' +--------+
|
===
GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de

I do not use pspice but SIMetrix Intro
http://www.catena.uk.com/Pages/download.html

 

[Wicked]

Sorry about that here is the topology of the filter: I can't use
SIMetrix it is required we do it in spice to turn in the file to show
the instructor.

 

[Malcolm Reeves]

Hi,

Have you put dc supplies on the schematic and connected them to the
op-amp? The "real" op-amps in pspice need supplies to work, just like
real ones really . For an ideal one you can use an E source or
Pspice's diff and gain parts. There might even be an ideal op-amp,
I've never looked.

Malcolm

Hello,

I just spent 3 hours trying to get Pspice to work! and it doesn't. =(
I am trying to make a high pass filter. The equation I am usuing is:

fc = 1/(2*pi*[(R1R2C1C2)^.5])
R1=R2 = 1.1K
C1=C2 = .1uf

fc = 1446Hz = 1.4Khz
(and I am usuing a reguar opamp on pspice to simulate this)

Can someone please help me? I just need to show the plot this on spice
to indicate this is a High pass filter and I have no idea why my
simulation isn't working. If possible please e-mail me the *.sch file
to [email protected]

Thank you very much!

--

Malcolm Reeves BSc CEng MIEE MIRSE, Full Circuit Ltd, Chippenham, UK
([email protected], [email protected] or [email protected]).
Design Service for Analogue/Digital H/W & S/W Railway Signalling and Power
electronics. More details plus freeware, Win95/98 DUN and Pspice tips, see:

http://www.fullcircuit.com or http://www.fullcircuit.co.uk

NEW - Desktop ToDo/Reminder program (free)

 

[Jim Thompson]

Hi,

Have you put dc supplies on the schematic and connected them to the
op-amp? The "real" op-amps in pspice need supplies to work, just like
real ones really . For an ideal one you can use an E source or
Pspice's diff and gain parts. There might even be an ideal op-amp,
I've never looked.

Malcolm

[snip]

There's the configurable OpAmp (PSpice symbol) on my website... you
can play with gain-bandwidth, swing, slew-rate, etc.

...Jim Thompson

 

[Wicked]

I used the "normal opamp" in Speice. The one that alread at the 15
volts pre-set the only pins I had were 2,3 and 6. I have no clue why
it isn't working...I have the files already setup and stuff if someone
wants to take a look at it.

Thanks

 

[qrk]

Hello,

I just spent 3 hours trying to get Pspice to work! and it doesn't. =(
I am trying to make a high pass filter. The equation I am usuing is:

fc = 1/(2*pi*[(R1R2C1C2)^.5])
R1=R2 = 1.1K
C1=C2 = .1uf

fc = 1446Hz = 1.4Khz
(and I am usuing a reguar opamp on pspice to simulate this)

Can someone please help me? I just need to show the plot this on spice
to indicate this is a High pass filter and I have no idea why my
simulation isn't working. If possible please e-mail me the *.sch file
to [email protected]

Thank you very much!

Your circuit has a corner freq around 2.2 kHz, as simulated in PSpice
using a model of a commercial opamp (AD8038. It also works fine using
a voltage controlled voltage source (E). As Malcolm states, be sure to
connect power to your opamp. PSpice has a component called "power".
It's a pretty power pin that is a macro for a DC voltage source.
Other things you must consider is your signal source and what type of
simulation you're trying to do (AC, transient,...). You need to use AC
simulation.

Since this looks like a homework assignment, you should post a screen
grab of your schematic in GIF format to the
alt.binaries.schematics.electronic group or to your web page so we can
see what your doing. It's probably a simple mistake. You should also
show us your netlist (filename.CIR and filename.NET). Can't learn much
if someone hands you the answer.

Mark

 

[Malcolm Reeves]

I used the "normal opamp" in Speice. The one that alread at the 15
volts pre-set the only pins I had were 2,3 and 6. I have no clue why
it isn't working...I have the files already setup and stuff if someone
wants to take a look at it.

Put them on a web page and post the link. Or a screen shot or the
..cir file netlist.

However, I'd guess that "normal opamp" in pspice is the part call
op-amp (which is in fact is just a e source table with a different
symbol, so does not need dc power). If you look at your netlist is it
the same as:

E_U1 out 0 VALUE {LIMIT(V($N_0001,out)*1E6,-15V,+15V)}
C_C1 $N_0002 $N_0001 100n
R_R1 0 $N_0001 1.1k
R_R2 out $N_0002 1.1k
C_C2 $N_0003 $N_0002 100n
V_V1 $N_0003 0 DC 0V AC 1V


I'm doing ac analysis so I have provided an ac source of 1V. The
result in probe are as expected.

Frequency VDB(out)
10 -86.4175211360673
31.6227766016838 -66.421254717561
100 -46.4584995412109
316.227766016838 -26.8224172235671
1000 -9.80877054973479
3162.27766016838 -1.65098907662067
10000 -0.17996333420589
31622.7766016838 -0.0181727760273795
100000 -0.0018270229388751

That's 2 points per decade 10-100kHz (click on trace name, paste and
copy)

Have you put in a sinewave generator instead of an ac source (although
you can still specify ac in a sinewave source, perhaps you have just
set the transient value). Have you got a 0V (AGND) symbol in the
circuit?



--

Malcolm Reeves BSc CEng MIEE MIRSE, Full Circuit Ltd, Chippenham, UK
([email protected], [email protected] or [email protected]).
Design Service for Analogue/Digital H/W & S/W Railway Signalling and Power
electronics. More details plus freeware, Win95/98 DUN and Pspice tips, see:

http://www.fullcircuit.com or http://www.fullcircuit.co.uk

NEW - Desktop ToDo/Reminder program (free)

 

[Wicked]

Yes, I have the analog ground and everything. I have an AC source I
dont see what can be wrong with my circuit. Can some please e-mail me
the *.sch file so I can see exactly what I am doing wrong. PLEASE!

Thank you

 

[Malcolm Reeves]

Yes, I have the analog ground and everything. I have an AC source I
dont see what can be wrong with my circuit. Can some please e-mail me
the *.sch file so I can see exactly what I am doing wrong. PLEASE!

I don't see why you can't upload your file. Or send it to me in an
email (send a quick message to the email address here as actually
getting through to me is a 2 stage process - spam, need I say more).

On s.e.d we are willing to help, just not willing to do someone's
homework . You're going to have to put your efforts forward
(netlist would be a start, say .cir and .net files).

If you have everything in the circuit correct, have you set up an ac
simulation? The default is just to do dc bias. Have you applied a dB
marker to the output or done add trace in the probe window?


--

Malcolm Reeves BSc CEng MIEE MIRSE, Full Circuit Ltd, Chippenham, UK
([email protected], [email protected] or [email protected]).
Design Service for Analogue/Digital H/W & S/W Railway Signalling and Power
electronics. More details plus freeware, Win95/98 DUN and Pspice tips, see:

http://www.fullcircuit.com or http://www.fullcircuit.co.uk

NEW - Desktop ToDo/Reminder program (free)

 

[qrk]

Yes, I have the analog ground and everything. I have an AC source I
dont see what can be wrong with my circuit. Can some please e-mail me
the *.sch file so I can see exactly what I am doing wrong. PLEASE!

Thank you

Post your .cir and .net files for this project. Without that
information, we can't help you. Those two files tell us what your
doing. Having us post the schematic file won't help you as it won't
show how the simulation is setup. The .net and .cir files show this
information.

BTW, this circuit works fine with the PSpice OPAMP symbol.

Mark