So essentially a resistor eats up/throws away energy?

[vmars]

I understand that a resistor can lower current flow at the expense of heat.
So essentially a resistor eats up/throws away energy?
Isn't there a better way to change current flow without throwing away energy?
Thanks!
...Vern

 

[Defennder]

Use a voltage source of lower voltage?

 

[NoTime]

I understand that a resistor can lower current flow at the expense of heat.
So essentially a resistor eats up/throws away energy?
Isn't there a better way to change current flow without throwing away energy?
Thanks!
...Vern

Yep, resistors turn energy into heat.

Sometimes the desired result is heat, say a toaster or room heater, so saying that energy is thrown away is incorrect.

In other cases a resistor can reduce the total energy consumed, so you have to look at the big picture.

In some cases alternate methods are used, for example switching power supplies.

 

[asynchronous13]

Isn't there a better way to change current flow without throwing away energy?

You can also use transistors to affect current flow. You'll still have power dissipated, though.

 

[turbo]

It is also possible that a resistor (or several of them) will supply a load to a power supply such that that power supply can supply a regulated drain instead of appearing like a high drain or a dead short.