Aaron's Homepage Forum
Aaron's Homepage Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 Electronics
 Power Supply
 12/120V inverter again
 New Topic  Reply to Topic
 Printer Friendly
Previous Page | Next Page
Author Previous Topic Topic Next Topic
Page: of 63

meerojak
New Member

1 Posts

Posted - Oct 28 2007 :  11:09:58 PM  Show Profile  Reply with Quote
Before this thread comes to an end, i read all replies from page 1 to the last page. whew! At least i got ideas. But i need an answer to this querry.
I need to light up a 10W, 0.230A fluorescent tube with a small 12v, 7.0 Ah lead acid battery. Does the schematic circuit modified by audioguru works in this just use a suitable transformer? What would the spec of that transformer would be? I used a DC choke 12v for 20W fluorescent tube, and it overheat when my load is only 10W. When I use a DC choke for 8W, my 10W fluorescent tube lights dimly. Any suggestions? thank you very much.

anthony
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - Oct 28 2007 :  11:57:37 PM  Show Profile  Reply with Quote
A 20W fluorescent tube needs a ballast for a 20W fluorecent tube. The ballast operates from the mains voltage and provides a high voltage to start the tube to light and limits the current.

Compact fluorescent light bulbs have an electronic ballast that steps up the voltage and provides a high voltage to start the tube to light and limits the current.

An inverter operating from 12V can supply mains voltage for either type of fluorescent light's ballast.
I have seen many inverters that use a center-tapped transformer.
I have never seen an inverter that uses a DC choke.

You said you tried a circuit with DC chokes that didn't work. Then please attach the schematic of the circuit so we can see what is wrong.
Go to Top of Page

Binary 1011001101
Nobel Prize Winner

United Kingdom
569 Posts

Posted - Nov 01 2007 :  3:21:26 PM  Show Profile  Reply with Quote
I can't seem to find any CCFL inverter schematics on the net so I can only give you this advise:

CCFL dirvers are quite complex, the tubes require a quick spike to get the tube ionized, once it is ionized it is a low resistance so current limiting is needed and a constant high voltage to keep it ionized...

There may be a way of driving it "hard" that I don't know of...

Also, whats with the massive space below your message?
Go to Top of Page

sanctajoe
New Member

Nigeria
1 Posts

Posted - Nov 02 2007 :  6:21:22 PM  Show Profile  Reply with Quote
h'llo Audioguru,can I uz another op-amp like PAO4(200w 20A) to boost the current feed-in to the driver transistor stage ?

sanctajoe
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - Nov 02 2007 :  8:05:58 PM  Show Profile  Reply with Quote
The PA-04 has many transistors and Mosfets and is not nedded for an inverter.
A 500W square-wave inverter just needs 2 power Mosfets driving a center-tapped transformer and driven from a CD4047 oscillator.
Go to Top of Page

lessthanchris1
New Member

1 Posts

Posted - Dec 02 2007 :  01:15:30 AM  Show Profile  Send lessthanchris1 an AOL message  Reply with Quote
Ok, I've made it through 20 pages, and I give up. Do you have a working 12V to 120V inverter plan in the 500W-1000W range?

Thanks
Go to Top of Page

tim
Mad Scientist

198 Posts

Posted - Dec 02 2007 :  10:51:03 AM  Show Profile  Reply with Quote
i think we all would agree by now that its much easier to just go out and buy a 12 volt 1000 watt inverter .
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - Dec 02 2007 :  12:18:01 PM  Show Profile  Reply with Quote
A Chinese 12V 1000W inverter is probably rated in Whats. It is probably 1000Watts for less than 30 seconds or 500Watts all day long.

A simple 500W to 1000W inverter can be made with a CD4047 ocillator driving two Mosfets into a center-tapped transformer. The output will be square-waves but many electronic items won't work from it.
Go to Top of Page

furquan
New Member

2 Posts

Posted - Dec 17 2007 :  11:35:27 AM  Show Profile  Reply with Quote
please explain the working of 9 volt dc to 120 volt ac inverter
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - Dec 17 2007 :  11:43:22 AM  Show Profile  Reply with Quote
quote:
Originally posted by furquan

please explain the working of 9 volt dc to 120 volt ac inverter



A 50Hz or 60Hz oscillator drives power transistors or power Mosfets to obtain high current at 50Hz or 60Hz. They drive a stepup transformer.
The output of this very simple circuit is square waves which are different to the sine-waves in the mains.
Go to Top of Page

tich
New Member

Lebanon
3 Posts

Posted - Jan 11 2008 :  10:43:57 AM  Show Profile  Reply with Quote
guys if i put a sine wave oscillator in place of the cd4047 i should be able to get a 500W sine wave oscillator right????
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - Jan 11 2008 :  4:11:10 PM  Show Profile  Reply with Quote
quote:
Originally posted by tich

guys if i put a sine wave oscillator in place of the cd4047 i should be able to get a 500W sine wave oscillator right????


Nope.
You will get 500W of heat for a moment then the output transistors will melt.
You don't convert a linear power amplifier into an inverter. It wastes as much power as its output. The wasted power makes a lot of heat.

A sine-wave inverter switches its outputs on and off at a high frequency. Then when switched on there is no voltage across the power Mosfets but the current is high. No voltage then no waste as heat. They switch quickly and the voltage of the many steps of the sine-wave is made by controlling the duty-cycle of the switching waveform using pulse-width-modulation.
Class-D power amplifiers work the same way and are very powerful without a lot of wasted heat.
Go to Top of Page

tich
New Member

Lebanon
3 Posts

Posted - Jan 12 2008 :  07:33:22 AM  Show Profile  Reply with Quote
ummm but i can use the obtained circuit as a 500W amplifier right?? i know this is off-topic and all i want is just a small reply. thx
Go to Top of Page

audioguru
Nobel Prize Winner

Canada
4214 Posts

Posted - Jan 12 2008 :  12:58:33 PM  Show Profile  Reply with Quote
Very few 500W audio amplifiers have enough cooling so they can have a continuous output of 500W. If they barely clip audio at 500W then their average power with most music is 50W. A PWM amplifier is much more complicated than a PWM inverter circuit. You can't hear the distortion from an inverter.
Go to Top of Page

tich
New Member

Lebanon
3 Posts

Posted - Jan 13 2008 :  05:51:50 AM  Show Profile  Reply with Quote
ok thank you for your support :D
Go to Top of Page
Page: of 63 Previous Topic Topic Next Topic  
Previous Page | Next Page
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
Aaron's Homepage Forum © 1995-2020 AARONCAKE.NET Go To Top Of Page
This page was generated in 0.14 seconds. Snitz Forums 2000