How to simplify this circuit ?

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AbdulAhad

Joined Oct 14, 2017
3
colored_schem.png
I am going to make a plasma speaker for my school science fair project.I have no previous experience in circuit building.Even the one on the bread board will work for me as I have to present it in front of my superiors.So a little help will be appreciated.colored_schem.png
Another problem that i am facing is that some of the parts are not available here in my city, so if you can also direct me which parts can i use instead.
NOTE:Once I'm back from shopping of the parts, I will update which parts were not found.
 

dendad

Joined Feb 20, 2016
3,317
I don't think you can simplify that circuit. In fact you need to add bits to it. You will need good bypassing on the supply lines and a tranzorb on the 24V in to absorb the switching transients I reckon. At least 10uF tantalum caps on the 7812 input and output, 0.1uF caps on the power pins of the SG3525 chip for a start. And I generally put the protection diode on the regulator as well. If the rest of the circuit will work or not I can't say, but I gather it must have come from somewhere.
If you want my advice, I' think you should start with something less dangerous, particularly as you say you have no circuit building experience. Be VERY careful!
You could kill yourself or others with this.
 
Last edited:

ian field

Joined Oct 27, 2012
6,539
View attachment 137297
I am going to make a plasma speaker for my school science fair project.I have no previous experience in circuit building.Even the one on the bread board will work for me as I have to present it in front of my superiors.So a little help will be appreciated.View attachment 137297
Another problem that i am facing is that some of the parts are not available here in my city, so if you can also direct me which parts can i use instead.
NOTE:Once I'm back from shopping of the parts, I will update which parts were not found.
If that's a CTV horizontal/EHT transformer, you might have trouble with the integrated diode-split multiplier - earlier designs had just the windings and an external Cockroft-Walton multiplier. The integrated types use the inter winding capacitance of layers of windings.

The transformer from a monochrome portable is much less likely to be diode-split and should be capable of a health corona discharge.

I assume you're aware that your audio signal must be used to modulate a frequency that the transformer can work with. In normal operation; the transformer will have the scan yoke and S correction capacitors all grouped together into a resonant system - the free standing transformer needs you to experiment for a frequency that works.

Some mono portable transformers had the EHT rectifier potted in - you may have to carefully file down the potting till you get at something the other end of the rectifier to solder to.

Transformers on CCFL backlight boards are another option for steep ratios - but I haven't got around to any experiments yet.
 

Dodgydave

Joined Jun 22, 2012
8,820
Certainly can help, Ditch the pulse transformer, ditch the four diodes on the outputs and drive the fets directly from the chip outputs, your chip is set up to give out complimentary pushpull mode, so i would make the primary winding on your flyback transformer a centre tap, and use the centre on the 12V rail, .

Or configure the chip to give a single parallel output and use one fet to pulse the flyback transformer like a standard lopt circuit.

flydriver1.png



Also you're not using the chips on-board feedback pins 1,2 for pwm control.
 
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