Guest Alun Posted April 18, 2005 Report Share Posted April 18, 2005 Why not?The PC's power supply converts the mains input voltage to DC before the switching regulator so the shape of the wave makes no difference whatsoever, you could run a PC off 290VDC if you wanted to. Most of my monitors are international and are rated for 100-240VAC so they have internal switch mode power supplies similar to that in my PC, if you don't like the idea of powering a monitor of one of these inverters, you could just use a TFT screen as they often are rated for 12V input, and even if they're not they certainly do have an internal switched mode power supply. :) Quote Link to comment Share on other sites More sharing options...
CheeseE Posted April 18, 2005 Report Share Posted April 18, 2005 Ok! so I can use it:)Now...I will build sasi's inverter with mosfets...But what are these 0.01 Ohm/5W resistors?And what is that MOV after the transformer? Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted April 18, 2005 Report Share Posted April 18, 2005 Hang on I wasn't thinking earlier on, just because my monitor might beable to handle squarewave it doesn't mean yours will, I'm sorry if I've confused you ???, I've done my best to exmplain this in the other thread:http://www.electronics-lab.com/forum/index.php?topic=3113.14 Quote Link to comment Share on other sites More sharing options...
Guest Kasamiko Posted April 19, 2005 Report Share Posted April 19, 2005 @SasiWhat's the update of your inverter..rhonn ;) ;) Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted April 19, 2005 Report Share Posted April 19, 2005 I am not recommending it not because of its squire wave output, but because of its switching between Mains and inverter. When mains power fails the inverter will start automatically after a fraction of seconds because of the relay switch. For PC cant sustain that time, it will get restarted.I'm sorry - hadn't read this thread from the beginning.This would be a big problem.However if you just used the inverter part of the circuit with out the mains switching relay, you could still use it to power a PC from a car battery providing the monitor can take the squarewave input.There are also ways to avoid this problem, one would be to increase the size of the filter capacitors in the PC's power supply so it can remain on during this short power cut. You could connect it up so mains transformer steps down the mains voltage to both charge the battery and power the inverter at the same time like in a proper UPS, then when the mains power goes down the battery power will immediately kick in and power the circuit. Quote Link to comment Share on other sites More sharing options...
CheeseE Posted April 19, 2005 Report Share Posted April 19, 2005 I won't use the switching relay, i will only use the inverter part in my car...so that not a problem...But what are these 0.01 Ohm/5W resistors? Is it 0.01 os 0.1?And whats's that MOV after the transformer? Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted April 19, 2005 Report Share Posted April 19, 2005 CheeseE,They are 0.01ohm resistors, or you could use 10 0.1ohm resistors in paralell.I think it might be better to use a large inductor instead of these resistors. The resistors are there to absorb the large current transients when both of the transistors turn on at once, a choke might be better as it would do the same job without dissipating energy all the time.The MOV thingy (I can't remember what MOV stands for) is a surge suppresser that absorbs any high voltage spikes that might be present on the output of the transformer.Did you read my post in the thread the following link leads to?http://www.electronics-lab.com/forum/index.php?topic=3113.14MP expresed a concern that your monitor might not like the squarewave output of this inverter. While my monitor will probably work from the square wave output yours might not.What sort of monitor do you plan to use with this inverter?If it's an TFT flatscreen then it'l work for sure, but if it's an old CRT you might not be so lucky.What does the label on the back of the monitor say?Does it say 100-240VAC 50/60Hz, or 230VAC 50Hz, or something completely different?Mine says 100-240VAC 50/60Hz so I know it'll work because the internal power supply in my monitor is like the one in my PC, it converts the AC to DC before it powers the device. If the label says 230VAC 50Hz you might not be so lucky but it's still worth a go, monitors aren't that expensive so you could easily pick one up that will work with this inverter at a very resonable price, you could always try ebay. Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 19, 2005 Report Share Posted April 19, 2005 Hi CheezE,If you use 0.1 ohm resistors instead of the required 0.01 ohms ones, they will each waste 28W of heat and cause the output voltage to be about 24V less at full load.The same applies to the resistance of your battery connectors and wiring if they are only 0.03 ohms. You're going to draw about 50A from a 12V battery! Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted April 19, 2005 Report Share Posted April 19, 2005 I agree with audioguru, if you must use 0.1ohm resistors use 10 in parallel, make sure each resistor is rated to at least 0.5W.What do you think of my idea to use an inductor instead of resistors audioguru? Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 19, 2005 Report Share Posted April 19, 2005 Hi Alun,Source resistors might not even be required since Mosfets are PTC. If the stongest one heats, its current decreases. Besides, the SG3525 has an adjustable deadtime contol so the outputs won't conduct simultaneously. :oThe current in an inductor builds slowly, so would cause a strange waveform. :o Quote Link to comment Share on other sites More sharing options...
CheeseE Posted April 19, 2005 Report Share Posted April 19, 2005 So if I use 0.1 Ohm resistors, then I need 4*10=40resistors? :o :o :oCan anybody send me the schematic with sg3525? I can't see it :'( :'(THX! :) Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted April 19, 2005 Report Share Posted April 19, 2005 Have a look here for the SG3526 schematic.http://www.electronics-lab.com/forum/index.php?topic=1360.14Resistors aren't expensive, but I agree the board space could be a problem, you might be able to omit the resistors anyway as audioguru said.What about your PC's monitor, are you sure it will work correctly when powered form this inverter? Quote Link to comment Share on other sites More sharing options...
CheeseE Posted April 19, 2005 Report Share Posted April 19, 2005 But it uses a different mosfets :/I can't buy them here...or can I use with irfz44?I don't know if the monitor will work....I will try it ;D ;DAnd if its not work, I will buy another... ;D Quote Link to comment Share on other sites More sharing options...
blitznet Posted April 19, 2005 Report Share Posted April 19, 2005 Hi Sasi,your inverter isn't so good. I always get my IRFZ44 overhead and I lost them.Does anyone have an experience like me? Quote Link to comment Share on other sites More sharing options...
Guest Kasamiko Posted April 20, 2005 Report Share Posted April 20, 2005 What's the used of 0.01/5 watts resistors anyway? ???Can't we just SHORT IT OUT??rhonn ;) ;) Quote Link to comment Share on other sites More sharing options...
CheeseE Posted April 20, 2005 Report Share Posted April 20, 2005 I photograph is missing:///Can U post it once again? Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 20, 2005 Report Share Posted April 20, 2005 Instead of using a half-dozen older Mosfets, why not use a modern one like the IRF2805 which is rated at 330W, and get 1KW from an inverter using only a single pair of them? ???They are probably used in the $40.00 500W inverters that I can buy at my local tire store. ;D Quote Link to comment Share on other sites More sharing options...
CheeseE Posted April 20, 2005 Report Share Posted April 20, 2005 What about IRF1405? I can only buy that here :'(55V169A330WRdson=0.00553 OTO220 AB Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 20, 2005 Report Share Posted April 20, 2005 Hi CheeseE,[move]Perfect! Quote Link to comment Share on other sites More sharing options...
audioguru Posted April 21, 2005 Report Share Posted April 21, 2005 Hey Sasi,The 1kW inverter will look like your little one when it uses a pair of those modern 330W Mosfets. ;D Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted April 21, 2005 Report Share Posted April 21, 2005 I think the transformer would be just a little bit bigger though. ;D Quote Link to comment Share on other sites More sharing options...
CheeseE Posted April 22, 2005 Report Share Posted April 22, 2005 Hi guys!I found some inverters...but only PCB...they are great!!!!:))Take a look here:(they are made with Protel)Pspsps2.zip Quote Link to comment Share on other sites More sharing options...
Guest Kasamiko Posted April 27, 2005 Report Share Posted April 27, 2005 @SasiThat look's Great!! ;DBTW: What's the rating of trafo you're using? the one in the picture..rhonn ;) ;) Quote Link to comment Share on other sites More sharing options...
Guest Kasamiko Posted May 8, 2005 Report Share Posted May 8, 2005 And this is the smallest inverter I have ever made....120VA used by my brother in his CAR.ITS very cute Quote Link to comment Share on other sites More sharing options...
Guest Kasamiko Posted May 9, 2005 Report Share Posted May 9, 2005 How many amperes?I'm planning to make a transformer using antenna ferite core.. :Drhonn ;) ;) Quote Link to comment Share on other sites More sharing options...
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