Why Do Homes Have Electrical Outlets with Constant Voltage?

[doublemint]

My friend asked me why do houses have electrical sockets that output a constant voltage rather than a constant current.
For the life of me, I couldn't answer it..

Anyone help me out?

Thanks,
DM

 

[berkeman]

My friend asked me why do houses have electrical sockets that output a constant voltage rather than a constant current.
For the life of me, I couldn't answer it..

Anyone help me out?

Thanks,
DM

The current drawn from the voltage source is dependent on the resistance of the load, according to Ohm's Law:

[STRIKE]V = V x R[/STRIKE] V = I x R

Or

I = V/R

Constant current sources have their applications in electronics, but not in power distribution. You use voltage sources for power distribution.EDIT -- Just to add a bit more... Common power sources like batteries and electric generators are voltage sources, not current sources.

 

[rollcast]

My friend asked me why do houses have electrical sockets that output a constant voltage rather than a constant current.
For the life of me, I couldn't answer it..

Anyone help me out?

Thanks,
DM

I forget now how it works (I'm sure some one can correct me) if you where to use constant current then the frequency would vary with load which would mean certain devices such as synchro motors wouldn't spin at a predictable speed.

 

[berkeman]

I forget now how it works (I'm sure some one can correct me) if you where to use constant current then the frequency would vary with load which would mean certain devices such as synchro motors wouldn't spin at a predictable speed.

If you used an AC current source, why would varying the frequency change the power output (to adjust to the load)? I'm not understanding what you are saying...

 

[rollcast]

If you used an AC current source, why would varying the frequency change the power output (to adjust to the load)? I'm not understanding what you are saying...

I asked my physics teacher this same question one time and he said that if you had a constant current ac source then the frequency wouldn't be constant and that would affect ac powered motors?

 

[Mark44]

The current drawn from the voltage source is dependent on the resistance of the load, according to Ohm's Law:

V = V x R

I'm sure you mean V = I x R.

Or

I = V/R

Constant current sources have their applications in electronics, but not in power distribution. You use voltage sources for power distribution.


EDIT -- Just to add a bit more... Common power sources like batteries and electric generators are voltage sources, not current sources.

 

[berkeman]

I'm sure you mean V = I x R.

Oops, thanks for catching my typo, Mark. I'll strikeout and fix my post above. Thanks.