What is the purpose of resistors in electrical circuits?

[Larrytsai]

I looked this up, and found that it limits the current going through, but say if we have a c ircuit with a power source and 1 resistor, the current through the resistor is the current coming out of the resistor.

I know if you hook the resistor up in parallel that is not the case, but in some circuits I have seen, they hook up the resistor in series, but what is the point?

 

[JaredJames]

The current going in certainly is the current going out, but that doesn't mean it's the current you'd get without the resistor.

Once the resistor is placed in you limit the entire circuit current immediately (series).

 

[Ken Natton]

Hmmm. The broad, generic answer that your question seems to seek would be something like this: Without any resistance in the circuit, what you have, of course, is a dead short. The purpose of any electrical circuit, electronic or otherwise, is to power some kind of load which itself provides an amount of resistance and is thus some form of resistor. From this it would seem reasonable to say that the purpose of any resistor in a circuit then is to act as a load with a view to in some way manipulating the electrical power. To understand the reasons why you would want to manipulate the electrical power in the various ways possible is of course, a question of the study of electronics. Is that what you were looking for?

 

[SamirS]

I looked this up, and found that it limits the current going through, but say if we have a c ircuit with a power source and 1 resistor, the current through the resistor is the current coming out of the resistor.

I know if you hook the resistor up in parallel that is not the case, but in some circuits I have seen, they hook up the resistor in series, but what is the point?

Hooking them up in a series could be useful if, for example, you need different voltages at different parts of the circuit, as there will be a certain voltage after the resistor depending on current and resistance, i.e. if you want to use devices on the same line that require different voltages.

 

[Bill_K]

As SamirS says, as a voltage divider. Also in combination with a capacitance, as an RC circuit to provide a desired frequency response.