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LT SPICE transformer

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MrDEB

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the transformer is each pri is 10 turns the sec is 30
keep getting node error.
it dosn't help when the help file is blank
why ???
 

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the transformer is each pri is 10 turns the sec is 30
keep getting node error.
it dosn't help when the help file is blank
why ???

hi D,
The secondary of the rightmost transformer is 'floating'.
Either add a normal ground symbol or the F4 'COM' and link back to 0V, via say a 1meg, as shown here.
 

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Thinking about it but there has to be a better way to drive a piezo tweeter.
Looking at using 1mh inductors as per EVIL GENIUS BOOK. see schematic in this thread and varying the output using taps (a 3 pos dip switch) to vary output frequency.
 
Hopefully if it works in simulation it SHOULD hopefully work for real.
Hopefully?

I don't see as it has any bearing on it working?, you can't accurately simulate either the transformer, the piezo's, or the actual audible output. The circuit is simple enough, a crude push-pull transformer coupled ampliifer.
 
The SIM program doesn't work probably because your coils are separate chokes instead of coupled together into a transformer.

You bought "cheep, cheep, cheep cluck cluck" no-name-brand piezo tweeters that have no datasheet and no spec's. So you don't know how much of a load they are on the transformer.
 
Another cheap Chinese piezo tweeter without a manufacturer's name and without a detailed datasheet.
Can you believe what they say?
 
Hopefully if it works in simulation it SHOULD hopefully work for real.
Hopefully?
Absolutely not, transformers and compound devices like piezo transducers don't simulate accurately, there's too many things that are dependent on their physical structure and environment for the simulator the manage. Even professional engineers have difficulty modeling devices like that in a simulator, and they're never quiet right.
 
The SIM program doesn't work probably because your coils are separate chokes instead of coupled together into a transformer.

This is WRONG, the coils are drawn as a transformer and defined with mutual coupling of 1 in the LTspice directive.

EDIT:
Added a cut down image of DEB's LTS file/image.
He had mistakenly made the K1 L1 L2 L3 1 DIRECTIVE a COMMENT
 

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Please note that inductor coupling in spice will not actually represent a real world transformer with any degree of accuracy. There are some transformer models on the Yahoo Groups LTSpice group, but not only are these models overly complicated for what you need they require a lot more information about the materials in the transformer than you probably have. There's really no point in simulating this in the first place as already mentioned. Simply use a dummy load resistor, tweak that resistors value until you get peak power output from your circuit, using that resistors value, and determining what the output impedance of your transducer is will give you the impedance you need to calculate the proper turns ratio and wire thickness of the primary and secondary of your transformer.

If all you want to do is simulate the amp output, all you need to do is use a dummy resistor with a value that matches the impedance of your piezo transducer at the frequency you're producing. If you don't know what that impedance value is you have nothing to simulate.
 
I am finding out that simulating a transformer is almost impossiable. Keep getting different readings etc depending on which way I have the inductor pointing (the one I am using has a little dot for polarity.)
going to build the push pull portion of schematic, connect to a 555 then use a d flipflop to alternate the two 3055 transistors for the push pull effect.
As for transducers, hopefully the ones I have will work.
Not sure what db sensitivity is. The tweeters are rated 94db sensitivity??
the push pull section is in this document http://googleads.sgdoubleclick.net/...superfindonline.com/index.php?search=ksn6001a
hopefully I can just connect the 555 and the D flip flop and get some output?
reason for using the amp in the schematic = I have about 10 of each 2n3055 and 2n3054 power transistors.
 
The link to your push-pull amplifier does not work. I get Google's home page.

There is a small horn piezo tweeter with less sensitivity and there is a longer horn one with more sensistivity (narrower angle). The sensitivity at a 20kHz peak is 94dB at a distance of 1m with an input that would produce 1W into 8 ohms (2.83V RMS) and at 4V RMS. Sound level drops at -6dB each time the distance is doubled plus humidity, wind and grass on the ground reduces high audio frequencies further.
 
I just tried the link and it works?
Is your computer on?? LOL
no idea why it dosn't work.
 
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