Resistance and resistors?

Question

i read in a book that some elctric household appliances such as electric stoves, irons,electric heaters, and electric radiator delivers heat(since there is changinf form electric energy into thermal energy) are resistors. do they mean that they contain metallic wires that are resitors?or any load or appliance that produces heat is a resistor?

another thing is any circuit the connecting wires have a certain resistance as well as some loads in a specific circuit, why we don't call them resistors and how do they differ from a resistor placed in a circuit.

please help coz i need to explain the lesson reistance and resistors and ia m having problmes in resistors.thx

Answer 1

(a)resistors are basically devices which oppose the flow of electric current....electri stoves and irons are literally called resistors because they posses some resistance....resistance is the ability to oppose the flow of current...basically all conductors have some resistance.....

(b)yes some loads and connecting wires has some resistance but they are not called resistors....the thing might be because the resistance they posses cannot affect current flow that much...that is they are insignificant...as for resistors...they are devices specifically designed to oppose current flow....for safety reasons in circuits...like to protect appliances that do not require too much current so the real resistors help to reduce current flowing into the circuit...hope you understand the long explanation thanx

Answer 2

You are correct about stoves and heaters having resistances in them; however to be precise, the resistance is rather low, so as to let a lot of amperage go through, hence they can dissipate a lot of power (and thus get really hot). Those are usually nickel-chromium alloy, which can stand the heat and resist corrosion.

The difference between the resistance of wiring and resistors as such, is that resistors are meant to have a resistance (to limit the intensity of the currnet going through the circuit). Wires do have an internal resitance, but the objective there is to hopefully have it as low as possible.

Answer 3

Every appliance produces heat, usually as a byproduct of it's operation. Some contain resistors, others don't, but usually the resistors are for other purposes than heat.

A few appliances produce heat as their design goal. Toasters, electric stove, electric heater are examples.

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