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Author Topic: Check my Resister Calculation  (Read 1110 times)


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Check my Resister Calculation
« on: January 13, 2004, 09:39:39 PM »

Ok.  I have some speakers that dont draw too much power.  I opened up them a few days ago to dye them, and they are fairly simple in design.  One of them has a circuit board in it with the power supply and amp.  Both speakers have wires connected to this amp (the one with the amp in it has an internal connection, the other one has a wire that runs between the speakers)

I want to relocate the circuit board to inside my computer and power it with a molex (and then run nice long wires out the back of my case to these speakers [I am using them as rear channel speakers])

On the transformer, it says it outputs 9 volts 300ma 2VA.  Using my crude and most likely wrong understanding of ohm's law, I need a 12/.3=40 ohm resister to drop 12 volts down to 9.  Before I go and blow something up, tell me anything I did wrong.
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Check my Resister Calculation
« Reply #1 on: January 13, 2004, 10:16:36 PM »

The amplifier circuit may not draw full current all the time.  Try using a 7809 voltage regulator to drop the voltage.
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