# Purpose of resistor

#### shibin_varghese

Joined Jan 14, 2019
73
It looks childish.
But I would like to get answers from all of you.
what is the function of a resistor in a circuit?

#### BR-549

Joined Sep 22, 2013
4,928
A resistor can have multiple purposes. It can adjust current. It can divide voltage and adjust voltage. It can generate voltage. It can generate heat.

It can give polarity to a signal. It can set and match impedance. It can adjust power.

And many many more things.

#### Ya’akov

Joined Jan 27, 2019
8,960
The choices for answer make no sense. Of course the purpose of a resistor is to be a resistor, and “current” isn’t a purpose. I could try to do mind reading but there’s no point really.

If you could explain what prompted you to ask this “question” we might be able to help answer it.

#### LvW

Joined Jun 13, 2013
1,749
To me, it is a rather "broad" question - however, it is a question that can be answered in principle.
Are we able to answer the question "what is the function of a capacitor in a circuit" ?
I think, yes we are.
So - why shouldn`t it be possible to answer this resistor related question?
However, it will be a collection of many answers.....one important task of a resistor in a circuit is, for example, to form - in conjunction with a capacitor - a time constant.This is a very important property in active filters and oscillators.

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#### dl324

Joined Mar 30, 2015
16,649
what is the function of a resistor in a circuit?
Such a general question can only be answered in general terms... A resistor resists the flow of current.

#### MrChips

Joined Oct 2, 2009
30,421
A resistor is placed into a circuit to irritate and confuse people who don't understand how circuits work.

Sorry, I couldn't resist.

#### OBW0549

Joined Mar 2, 2015
3,566
what is the function of a resistor in a circuit?
It's function is to serve whatever function the circuit designer intended.

#### LvW

Joined Jun 13, 2013
1,749
I find it a little sad that many answers make fun of the question.
Admittedly, it is a very general question - but it is a question to which a factual answer is possible.
Let's assume that a beginner (student) asks this question - it would be embarrassing if I couldn't give him a substantial answer to it and had to fob him off with silly sayings.

#### MrChips

Joined Oct 2, 2009
30,421
Maybe. But voltage, current, and resistance are some of the first things one learn in junior high school level physics.

#### Ya’akov

Joined Jan 27, 2019
8,960
I find it a little sad that many answers make fun of the question.
Admittedly, it is a very general question - but it is a question to which a factual answer is possible.
Let's assume that a beginner (student) asks this question - it would be embarrassing if I couldn't give him a substantial answer to it and had to fob him off with silly sayings.
There is no answer to "what is the function of a resistor in a circuit?" that has any substance. A particular resistor in a particular circuit, yes, but there is no general case.

What does a resistor do? That could be answered, but that's not its "function in a circuit" which depends on the circuit and where the resistor is.

If a beginner asked the question, I would give this very answer because the question can only be from ignorance of these facts.

#### Tonyr1084

Joined Sep 24, 2015
7,756
A resistor is a simple passive device. It does what its name suggests - it resists. It resists the flow of electrons, or in other words, it resists current. There are many uses for them but basically they are just devices that only resist the flow of electrons. When they do they get hot. Depending on how much current is going through the resistor and what voltage is applied you can calculate the wattage the resistor is converting to heat.

A resistor comes in a few basic forms. The most common resistor either has two wire leads or two metalized ends. In the case of wire leads, it's called a "Through Hole Component". Where the ends are metalized (for purposes of soldering) they are called SMD's (Surface Mounted Devices).

To name a few other forms of resistors there are the likes of which you probably know as a volume control. This is more appropriately known as a Potentiometer (or "Pot" for short). It's just a variable resistor that you can control. There are LDR's (Light Dependent Resistors) that change their value with the amount of light that falls on them. There are resistors that automatically change their value (called MOV's or Metalized Oxide Varistors). They change as they heat up.

There are a large number of other types of resistors as well. But they all do a simple task - that of resisting current. Depending on how you use them they can form many different circuits for many different uses as previous answers have highlighted. But in the end, a resistor is just a basic passive device. Passive because it does not do any calculations or perform any functions. It just resists. Even when resistance is futile, it resists.

#### Ylli

Joined Nov 13, 2015
1,083
The function of a resistor is to convert current flow into voltage drop.

#### MrChips

Joined Oct 2, 2009
30,421
A resistor is used to reduce the current or voltage when the current or voltage is too high.

#### BR-549

Joined Sep 22, 2013
4,928
A resistor is an automatic proportional valve.

#### crutschow

Joined Mar 14, 2008
33,969
A resistor obeys Ohm's law of I = V/R.
By rearranging, we also get V = I*R and R = V/I, where V is the voltage drop across the resistor terminals, I is the current through the resistor, and R is the resistor resistance in ohms.

So in a circuit the resistor function is to follow Ohm's law.

#### MrChips

Joined Oct 2, 2009
30,421
I say it's the other way around.
Which one came first, Ohm's Law or the resistor?
The resistor came first. Ohm's Law describes the behaviour of the resistor.

#### crutschow

Joined Mar 14, 2008
33,969
I say it's the other way around.
Which one came first, Ohm's Law or the resistor?
The resistor came first. Ohm's Law describes the behaviour of the resistor.
I don't see the significance of that chicken and egg distinction as pertains to my post.
In a circuit you want a device whose function it is to follow Ohm's law, and that device is a resistor.