If the resistor converts energy to heat then are you wasting energy whenever you use a resistor?
I will not call it a “waste” I will call it a loss. That’s why,
in the real world, there is no ideal system where no energy is lost. In fact, the efficiency of a system is measured by the amount of energy it loses to the environment.
Thus, saying it is a waste means that the loss of energy in its environment is not a prerequisite to achieving your goal when using resistance.
power is a measure of work. heat is a by-product of work. you can think of heat as a waste, and we often talk about lost heat. or you can build the circuit if all the resistors are in the same place and put your cup of coffee on it. then the heat will work too: heat your coffee.
Believe it or not, some of the greatest engineers are known to be great because they figured out how to get what others thought wasted for them.
The laws of thermodynamics state that you are always wasting energy (increasing entropy) no matter what you do. Thus, even though a resistor dissipates energy in the form of heat, it is also an uneven component in most electronic circuits that can do a lot of useful things. The use of a resistor can therefore always be the most effective solution for a particular circuit. Another problem with resistors is that they generate noise. There are therefore many intelligent circuits that try to reduce or completely eliminate the number of resistors.
As ian Lang said, there is a lot of energy lost in the form of heat produced in electronics – like computers. in fact, almost all the electrical energy supplied to a computer is transformed into heat. but very little comes from discrete resistances. almost all of the heat is produced by the transistors in the power supply and integrated circuits. they are designed to produce as little heat as possible, but still produce a lot.
but the lost heat is inevitable. Gas engines and power plants waste more than half of the energy in the fuel. and with the current technology, few improvements are theoretically possible.
yes, it’s a perfectly correct assumption.
Resistances always transform energy into heat, and heat can or can not be used to our advantage.
Electric heaters, toasters and incandescent bulbs are good examples of resistance in which the heat generated is beneficial.
Electronic circuits use many resistors to help us generate proper voltages and currents for the desired operation. because they heat up, they are carefully chosen to do their job with minimal loss.
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no, you are not always wasting energy. or, more precisely, the amount of energy wasted in many cases can be minimal.
example, an ip application requires a high impedance voltage divider with resistances in the megohms. the loss of power could be in the micro-watts, because the currents transmitted could be micro-amps. On the other side of the equation, a neutral grounding resistance of an electrical substation can reach 300 milli-ohms. However, if the neutral line currents become too high, the resistor is designed to absorb hundreds balanced AC line. it goes without saying that this type of resistance can be very large, depending on the nominal values.
