I have a 9805 Voltage regulater putting out a steady 5 volts.My question is,(The npn transister is getting wiegh to hot.So i want to cut the power down.Lets say i want the 9805 to putt out abought 2 or 3 volts,How do i determen which resister to use?How is this dun?and also is 5 volts too much to run the resister?..............I would like to go from the battery then 9805 then a resister to load then ground.

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huhh it never works twice...

 

first of all, is that a 9805 or is it a 7805??

can u attatch a schematic of your circuit?

because no one knows which NPN transistor are u talking about. maybe it is supposed to be hot because of high currents. usually dropping the voltage with a single resistor is not a good idea and its a big waste of energy. this might be a big issue in battery operated systems. maybe u made the circuit wrong. u can give us a link of the circuit so we could see what u are trying to do and where u went wrong

 

ghoattriple

You must change the 9805 or 7805 for a LM317 if you want 2 to 3 volts output.

Ante :roll: