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Re: Pease tuneable MFB band-pass filter

 

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What I wrote:This sub-circuit name is not defined.X1 3 2 8 4 1 UniversalOpAmp was copied from the Spice output log.

On 2025-05-16 18:16, Tony Casey via groups.io wrote:
There is no .subckt named "universalopamp". It's called "level1".

--
Regards,
Tony

On 16/05/2025 18:40, John Woodgate via groups.io wrote:
This sub-circuit name is not defined.
X1 3 2 8 4 1 UniversalOpAmp

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Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion

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Re: Pease tuneable MFB band-pass filter

 

I looks like the level1 reference is being satified by the reference to UniversalOpAmp1.lib, which contains level1.? I created this by placing the UniversalOpAmp from the LTspice opamp menu and then by viewing the netlist was able to create my 'OpAmp.sub.


Re: Simulating a testofon

 

On Fri, May 16, 2025 at 05:15 PM, Andy I wrote:
I don't know what a testofon (or testafon) is
It's a very great measuring device. It converts a resistance to a frequency. R10 is a simulates resistance between the test tips. R7 is the speaker.
With a testofon you can measure on a simple and quick way if a component is damaged (for example a transistor, diode, resistor, switching contacts, etc.). You can mesure under voltage, too. D1, R1 and D2 protects the testofon from damage due to external voltage.
?
Add "startup" to the .TRAN directive.
?
Thanks, that's the solution.
--
Klaus


Re: Pease tuneable MFB band-pass filter

 

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Be careful using a file named "opamp.sub" and a .subckt named "opamp". These names are already used in the default LTspice installation - see "opamp" symbol in the the Component Chooser (F2).

--
Regards,
Tony

On 16/05/2025 18:59, Tim Hutcheson via groups.io wrote:

John does your OpAmp.sub look like this?
?
.SUBCKT OpAmp 0 N003 V+ V- OUT
X1 0 N003 V+ V- OUT level1 Avol=1Meg GBW=10Meg Vos=0 En=0 Enk=0 In=0 Ink=0 Rin=500Meg
.lib UniversalOpAmp1.lib
.ENDS
?
It runs fine here.


Re: Pease tuneable MFB band-pass filter

 

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That's not the problem. You have not called for .lib UniversalOpAmp1.lib on your schematic.

On 2025-05-16 17:59, Tim Hutcheson via groups.io wrote:
@John Woodgate
?
John does your OpAmp.sub look like this?
?
.SUBCKT OpAmp 0 N003 V+ V- OUT
X1 0 N003 V+ V- OUT level1 Avol=1Meg GBW=10Meg Vos=0 En=0 Enk=0 In=0 Ink=0 Rin=500Meg
.lib UniversalOpAmp1.lib
.ENDS
?
It runs fine here.
?
Tim
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion

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Re: Pease tuneable MFB band-pass filter

 

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There is no .subckt named "universalopamp". It's called "level1".

--
Regards,
Tony

On 16/05/2025 18:40, John Woodgate via groups.io wrote:

This sub-circuit name is not defined.
X1 3 2 8 4 1 UniversalOpAmp


Re: Pease tuneable MFB band-pass filter

 

Be careful naming a file "opamp.sub" and a .subckt of the same name. There is already an "opamp" and an "opamp.sub" in the LTspice installation.

--
Regards,
Tony


On Fri, 16 May 2025, 19:00 Tim Hutcheson via , <thutcheson=[email protected]> wrote:
@John Woodgate
?
John does your OpAmp.sub look like this?
?
.SUBCKT OpAmp 0 N003 V+ V- OUT
X1 0 N003 V+ V- OUT level1 Avol=1Meg GBW=10Meg Vos=0 En=0 Enk=0 In=0 Ink=0 Rin=500Meg
.lib UniversalOpAmp1.lib
.ENDS
?
It runs fine here.
?
Tim


Re: Pease tuneable MFB band-pass filter

 

Those 0 and N003 node names could be IN- and IN+, but I don't think that matters - they just transfer the connections


Re: Pease tuneable MFB band-pass filter

 

@John Woodgate
?
John does your OpAmp.sub look like this?
?
.SUBCKT OpAmp 0 N003 V+ V- OUT
X1 0 N003 V+ V- OUT level1 Avol=1Meg GBW=10Meg Vos=0 En=0 Enk=0 In=0 Ink=0 Rin=500Meg
.lib UniversalOpAmp1.lib
.ENDS
?
It runs fine here.
?
Tim


Pease tuneable MFB band-pass filter

 

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It won't run. ERROR: C:\Users\User\Downloads\Pease MFB BP filter (2)\Pease MFB BP filter (2)\OpAmp.sub(7): This sub-circuit name is not defined.
X1 3 2 8 4 1 UniversalOpAmp
??????????? ^^^^^^^^^^^^^^^

I find I have to download my uploads to Downloads and run from there , to check that the upload does work.

On 2025-05-16 17:30, Group Notification wrote:

The following items have been added to the Files area of the [email protected] group.

By: Tim Hutcheson <thutcheson@...>

Description:
Pease Filter with an OpAmp.sub that wraps the UniversalOpAmp device for easy substitution by name for any pincompatible opamp (I think). :-)

--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion

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Re: Simulating a testofon

 

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It's 'Solder pads for test leads'. It buzzes if R10 is low enough, so it's a continuity tester. I suppose the PTC in the picture is protection against the test leads being connected to a significant voltage.

On 2025-05-16 16:15, Andy I via groups.io wrote:
On Fri, May 16, 2025 at 11:01 AM, Klaus W?rner wrote:
I try to simulate a testofon, but it doesn't work. Has anyone an idea, why?
I don't know what a testofon (or testafon) is, but I think it is a buzzer?? Does it make an audible buzzing sound when the leads connect?
?
From the looks of the schematic, it seems like there should be a voltage source connected at the far left end.? Otherwise, why would the diodes be there?? I do not know how to speak German so I don't know what the picture says.
?
If the rest of the circuit is supposed to be an oscillator, then maybe it needs more time to start oscillating.? Or, maybe it needs a smaller timestep.? If I change the simulation command from this:
.tran 1s
to this:
.tran 0 1s 0 1u
then the output signal shows a strong oscillation.
?
The problem is that SPICE/LTspice is a discrete time simulator.? It does not simulate in continuous time.? It chooses timesteps based on what is already happening in the circuit.? If it is not oscillating yet, then the timesteps might be too far apart, to get it oscillating.? And then it never knows to make the timesteps smaller, which might be needed in order for it to oscillate.
?
Andy
?
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion

Virus-free.


Re: Simulating a testofon

 

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On 16/05/2025 17:01, Klaus W?rner via groups.io wrote:
I try to simulate a testofon, but it doesn't work. Has anyone an idea, why?
Add "startup" to the .TRAN directive.

--
Regards,
Tony


Re: Pease tuneable MFB band-pass filter

 

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The circuit does require quite a high GBW. With the 4562, it begins to lose gain above 50 kHz peak frequency.

On 2025-05-16 15:55, Andy I via groups.io wrote:
I forgot to mention -
?
I also uploaded "Pease MFB BP filter with UnivOpAmp2.zip" to the Temp folder.? It substitutes the UniversalOpAmp2 in place of the LM4562, and it moves the "OUT" node to the right place.
?
I see that John has also updated his file again, to move the "OUT" node to where it should be.
?
His schematic kept the LM4562, so you can compare it against the UniversalOpAmp2 in mine.
?
Andy
?
?
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion

Virus-free.


Re: Simulating a testofon

 

On Fri, May 16, 2025 at 11:01 AM, Klaus W?rner wrote:
I try to simulate a testofon, but it doesn't work. Has anyone an idea, why?
I don't know what a testofon (or testafon) is, but I think it is a buzzer?? Does it make an audible buzzing sound when the leads connect?
?
From the looks of the schematic, it seems like there should be a voltage source connected at the far left end.? Otherwise, why would the diodes be there?? I do not know how to speak German so I don't know what the picture says.
?
If the rest of the circuit is supposed to be an oscillator, then maybe it needs more time to start oscillating.? Or, maybe it needs a smaller timestep.? If I change the simulation command from this:
.tran 1s
to this:
.tran 0 1s 0 1u
then the output signal shows a strong oscillation.
?
The problem is that SPICE/LTspice is a discrete time simulator.? It does not simulate in continuous time.? It chooses timesteps based on what is already happening in the circuit.? If it is not oscillating yet, then the timesteps might be too far apart, to get it oscillating.? And then it never knows to make the timesteps smaller, which might be needed in order for it to oscillate.
?
Andy
?


Simulating a testofon

 

Hi,
?
I try to simulate a testofon, but it doesn't work. Has anyone an idea, why?
?
--
Klaus


Re: Pease tuneable MFB band-pass filter

 

I forgot to mention -
?
I also uploaded "Pease MFB BP filter with UnivOpAmp2.zip" to the Temp folder.? It substitutes the UniversalOpAmp2 in place of the LM4562, and it moves the "OUT" node to the right place.
?
I see that John has also updated his file again, to move the "OUT" node to where it should be.
?
His schematic kept the LM4562, so you can compare it against the UniversalOpAmp2 in mine.
?
Andy
?
?


Re: Pease tuneable MFB band-pass filter

 

On Fri, May 16, 2025 at 08:34 AM, Tim Hutcheson wrote:
Btw, it occurs to me because of this that a nice feature for LTspice would be to be able to simply change the opamp name on the schematic to UniversalOpAmp to avoid having to place it.
That actually does work too, except for these two things:
  1. You must remember to also add a ".lib" command to the schematic to load the necessary library file.
  2. The actual subcircuit names of the UniversalOpAmp* models are "level1", "level2", "level3a", "level3b", and "level4".
?
Therefore, it is actually easier (IMO) to just place the new symbol in place of the old one.? It takes care of everything automagically.
?
Andy
?


Re: Pease tuneable MFB band-pass filter

 

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That's what I have now done, but I had strange difficulty in getting rid of the .ASC with the wrong OUT flag.

On 2025-05-16 15:24, Andy I via groups.io wrote:
I agree, a fixed schematic is best.? It would be even better if John had moved the "OUT" node name to the right place.? Oh well.
?
But it really was trivial to delete the ".inc" command and the op-amp symbol, and place a new UniversalOpAmp2 symbol in its place.? That's three steps, and done.? For me, I did not find it harder (in fact it's easier) than editing the name next to the op-amp symbol, and it is much easier than also adding the parameters on the other three Attribute lines if they are needed for it to work right.? Still, some are unaware of the UniversalOpAmp* components and how they work.
?
Analog Devices did mess things up quite a bit by splitting the UniversalOpAmp component into seven distinct components, which now cause confusion when users try using them for the first time and discover that they might not behave like op-amps do.? They should have left it alone.
?
Andy
?
?
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion

Virus-free.


Re: Pease tuneable MFB band-pass filter

 

I agree, a fixed schematic is best.? It would be even better if John had moved the "OUT" node name to the right place.? Oh well.
?
But it really was trivial to delete the ".inc" command and the op-amp symbol, and place a new UniversalOpAmp2 symbol in its place.? That's three steps, and done.? For me, I did not find it harder (in fact it's easier) than editing the name next to the op-amp symbol, and it is much easier than also adding the parameters on the other three Attribute lines if they are needed for it to work right.? Still, some are unaware of the UniversalOpAmp* components and how they work.
?
Analog Devices did mess things up quite a bit by splitting the UniversalOpAmp component into seven distinct components, which now cause confusion when users try using them for the first time and discover that they might not behave like op-amps do.? They should have left it alone.
?
Andy
?
?


Re: Pease tuneable MFB band-pass filter

 

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I've updated to include the 4562 model file.

On 2025-05-16 14:36, Tim Hutcheson via groups.io wrote:
I was suggesting that,as in this case a device include is missing (happens often), if I could comment out the ".inc LM4562_NS.sub", and supposing I had many opamps that use that model, It would be nice not to have to cut and replace those with a new placement of? UniversalOpAmp2, just replacing the names could be made sufficient (ADI change required).
?
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion

Virus-free.