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Voltage Matching


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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.

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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.

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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.

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