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eddielim
New Member
3 Posts |
 Posted - Oct 23 2009 : 10:00:59 PM
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| what's the operation of this circuit , and what's the function part by part ? |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Oct 24 2009 : 10:15:07 AM
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| It's an oscillator that pings and inductor. The flyback current is rectified and used as the output to make 12V. |
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eddielim
New Member
3 Posts |
Posted - Oct 24 2009 : 11:26:11 AM
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| what is the main component/part to cause the voltage step-up? |
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eddielim
New Member
3 Posts |
Posted - Oct 24 2009 : 11:39:00 AM
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| whats the application ? and its a class B amplifier ?? |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Oct 25 2009 : 10:47:29 AM
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Why are you asking these questions? It sounds like you are trying to do a homework assignment.
There is no "main" component causing a voltage increase. The entire circuit works to drive the inductor, as I mentioned in the first post. |
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maxtarco
New Member
4 Posts |
Posted - Nov 05 2009 : 4:32:00 PM
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See now, I don't know much about electronics - well, not enough at least - to know if this is a stupid question, but: What would happen if I substituted Q1,Q2 and/or Q3 with something like a TIP42C?
** Due to laws-against-blowing-things-up-in-the-house, imposed by my wife (after incident #67b: "The day I blew up the microwave, attempting to make plasma...") I cannot, by law, test something unless I'm at least 99.9% sure it would work. ** |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Nov 08 2009 : 11:14:21 AM
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That's funny. I've blown up some microwaves in my time. 
The circuit is a simple multivibrator with it's output connected to drive Q3, which switches the inductor on and off. As the magnetic field collapses when current is cut, a high voltage is induced back into the inductor. This is rectified by D2 and filtered by C3. D3, R7, R8 and Q4 form a very simple voltage regulator by controlling the base current of Q3.
The multivibrator stage can be made with most any signal transistor. The drive transistors can be substituted as well, just compare the gain specs on the transistor you want to substitute with that specified and make sure it is similar. |
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maxtarco
New Member
4 Posts |
Posted - Nov 08 2009 : 1:14:59 PM
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lol that's brilliant.
And I think you might have answered eddielim's question as well.
I think this is a great informative site.
Thanx! |
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maxtarco
New Member
4 Posts |
Posted - Nov 08 2009 : 1:39:53 PM
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Here's what I'm attempting:
I designed a crude cooling system, using a DC12v 0.13A PSU fan, for cooling my laptop - I despise these bulky, flat bed cooling pads you have to put underneath the laptop - and I've had some awesome results with my system (cooling from 48Celcius to 18Celcius at peak - and I'm aiming for below 16Celcius), connected to the laptop's main transformer, but less than 20% efficiency (cooling from 48Celcius to 37Celcius), connected to the usb's standard DC5v power supply.
Would this converter be able to convert the usb DC5v to at least the DC12v 0.13A I require? Which is why I asked about TIP42C, because they have such high outputs.
** And NO, I prefer making something to buying - It's more rewarding and fun!  ** |
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Aaron Cake
Administrator
Canada
6718 Posts |
Posted - Nov 09 2009 : 4:20:52 PM
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Should work on 5V just fine, with a greater current draw of course. For such little current, the TIP42 is overkill but should work. It has a high voltage drop compared to smaller signal transistors though.
Why not use a 5V fan? |
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maxtarco
New Member
4 Posts |
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6V to 12V converter
