Jerrykevnov Posted June 11, 2004 Report Share Posted June 11, 2004 I'm new to the form and have a question. Is it possible to have a circuit match a variable voltage and also increase the ouput current. Some information: Computer power supply (Antec TRUE480) has a Fan Only connector that changes the voltage which changes speed of fans. I need more power output for more fans. So I need to vary a seperate 12v line to match the Fan Only voltage. Any help would be greatful. Quote Link to comment Share on other sites More sharing options...
Kevin Weddle Posted June 11, 2004 Report Share Posted June 11, 2004 You might consider that this is a signal that is biased around 12 volts. Use a transistor which will give you the voltage you need under higher current. I think you need a high current transistor because it will allow you to get a reasonable amount of gain. In other words, let's say the load resistance is 12 ohms with a common emitter configuration. The high current transistor will have a low value emitter resistor because of the high current. This gives you a reasonable gain. A low current transistor would have a large emitter resistor and the gain will be low. Also, with a higher current transistor you can have a greater change in VCE and still stay within the power rating. Quote Link to comment Share on other sites More sharing options...
audioguru Posted June 11, 2004 Report Share Posted June 11, 2004 Jerry,Welcome to our forum.How much current do you need?Do you have a higher voltage available, so that the "current booster" can have some headroom? Quote Link to comment Share on other sites More sharing options...
Jerrykevnov Posted June 11, 2004 Author Report Share Posted June 11, 2004 I probably could get away with adding a second leg for more voltage for headroom. I only need probably a max of 1-2 amps. This is for running some case fans so they aren't to power hungry. Quote Link to comment Share on other sites More sharing options...
MP Posted June 11, 2004 Report Share Posted June 11, 2004 Hi Jerry, can you tell us anything about the existing circuit that is now running the fan?MP Quote Link to comment Share on other sites More sharing options...
Jerrykevnov Posted June 15, 2004 Author Report Share Posted June 15, 2004 I have not opened the power supply to look at the circuit because I don't want to void the warranty.http://www.antec.com/us/pro_details_powerSupply.php?ProdID=20480#This is the page for the power supply with some of the specs. I don't think they give enough information but then maybe they do.I just need a circuit that i can plug into the supply and give me more power output with the matched voltage of the "Fan Only" connector. The"Fan Only" connector varies from ~5-12V depending on the temperature that the supply reads. I have found circuits that are temperature controlled but I don't need to have another temp. sensor if I have a sensor already. Then it's jsut a matter of voltage matching.I don't even know if this can be done. Thanks for any help. Quote Link to comment Share on other sites More sharing options...
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