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Re: Pease tuneable MFB band-pass filter
开云体育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". --
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 |
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.
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Thanks, that's the solution.
--
Klaus |
Re: Pease tuneable MFB band-pass filter
开云体育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:
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Re: Pease tuneable MFB band-pass filter
开云体育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:
--
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 |
Re: Pease tuneable MFB band-pass filter
开云体育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. |
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:
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Pease tuneable MFB band-pass filter
开云体育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. 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:
--
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 |
Re: Simulating a testofon
开云体育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:
--
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 |
Re: Simulating a testofon
开云体育On 16/05/2025 17:01, Klaus W?rner via
groups.io wrote:
Add "startup" to the .TRAN directive. --
Regards, Tony |
Re: Pease tuneable MFB band-pass filter
开云体育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:
--
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 |
Re: Simulating a testofon
On Fri, May 16, 2025 at 11:01 AM, Klaus W?rner wrote:
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:
to this:
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
? |
Re: Pease tuneable MFB band-pass filter
I forgot to mention -
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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.
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I see that John has also updated his file again, to move the "OUT" node to where it should be.
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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:
That actually does work too, except for these two things:
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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
开云体育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:
--
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 |
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
开云体育I've updated to include the 4562 model file. On 2025-05-16 14:36, Tim Hutcheson via
groups.io wrote:
--
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 |