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7905 regulator?

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lilshawn:
you will find often amplifiers using  - voltages. to drive the speakers better they use a - voltage and a + voltage so if you use -5 and + 5 you can effectively get 10 volts from peak to peak. not only does this simplfy the circuit, you more efficiently use your power this way. (not throwing away power trying to invert the power later on)

this is called potential difference. The voltage between A and C is the sum of the voltage between A and B and the voltage between B and C... it's where you place your load that determines how much that is. if A and B is -5 volts and B and C is 5 volts then -5+5=10 volts... i know the math is wrong right??

-5 volts is 5 volts away from 0 volts ( what is that arbitrary point we called "Ground") and +5 volts is 5 volts away from 0 volts. so 5+5=10

the voltages don't even have to be the same. if you had -12 and +5 you get 17 volts. -62 and +90 volts would be 152 volts.

SavannahLion:
I'd imagine the math would be 5-(-5)=10.

I know what your point is, eeking 7v is an old trick to downgrade 12v fans in PCs.

lilshawn:

--- Quote from: SavannahLion on October 19, 2011, 01:23:13 pm ---I'd imagine the math would be 5-(-5)=10.

I know what your point is, eeking 7v is an old trick to downgrade 12v fans in PCs.

--- End quote ---

I know what I was after... I maths fail. in all manners of maths.  ;D

SavannahLion:

--- Quote from: lilshawn on October 19, 2011, 03:09:14 pm ---
--- Quote from: SavannahLion on October 19, 2011, 01:23:13 pm ---I'd imagine the math would be 5-(-5)=10.

I know what your point is, eeking 7v is an old trick to downgrade 12v fans in PCs.

--- End quote ---

I know what I was after... I maths fail. in all manners of maths.  ;D

--- End quote ---

I know what you know what you was after.  :cheers:

Ed_McCarron:

--- Quote from: SavannahLion on October 19, 2011, 01:23:13 pm ---I know what your point is, eeking 7v is an old trick to downgrade 12v fans in PCs.

--- End quote ---

On an unrelated (well, kinda related) topic, using cheap 1N4148 diodes for their .7v drop (stack a bunch in series) is a cheap hack here.

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