Can I Replace a 0.5W Resistor With Two 0.25W Resistors in Series or Parallel?

Question

Hello!
By connecting two or more resistors in series, their resistances add up and what about their power? For example, I can replace one 0.5W resistor with two 0.25W resistors or what does it look like?

Regards

CMS · Answer

power is added can you use 2x0.25 instead of 0.5 as you write?

kankan · Answer

Hello!

Exactly. The power dissipated in the resistor is P=I²*R. When replacing two resistors with one with a resistance equal to those two, the power of a single resistor must be at least equal to the sum of the powers of the two.

Regards!

Anonymous · Answer

When connected in series, ohms are added and power is subtracted
When connected in parallel, the ohms are halved and the powers are added together. The case is different with capacitors

reading material: http://www.edw.com.pl/pdf/k01/02_09.pdf

szod · Answer

The power of what is subtracted from what? When connected in series, the power dissipated is divided into two resistors, so in total you can dissipate twice as much power on them. So the powers of resistors connected in series are added the same way as resistors connected in parallel. Simply by connecting two of the same resistors in series the voltage is evenly distributed in half on each of them. When connected in parallel, you have the same voltage on each but in turn the current splits in half. That's right - a reader.

Anonymous · Answer

szod or if you connect 2 resistors of 0.5W each in series, according to your theory it should give 1W? And when you let go through the first 1W resistor, what do you think will happen to it? (the first one is still 0.5W) then you will probably need this reading

staszeks · Answer

that is, if you connect two 0.5W resistors in series, you get a 0W resistor????

CMS · Answer

this is interesting then why, instead of a 5w resistor, I gave 5 x 1w, they did not evaporate, according to your theory, they should and do not even heat up what about incandescent bulbs, won't two hundreds connected in series pull two hundred watts by chance??

pmxxyz · Answer

Bulbs are designed for a specific voltage, e.g. 230V (and have a specific resistance so that a specific current flows at 230V). Connecting in series 2 identical light bulbs for the same voltage (230V) will make each get half the voltage (and certainly less power will be emitted in it - or ideally half, it must be measured, because the light bulbs are non-linear receivers). The topic is purely philosophical. The question is how much theoretically you can separate in resistors, at a given connection. The logical (and general) answer is: the more resistors, the more power theoretically can be dissipated (under certain conditions). And the specifics depend on the specific situation (see the example with light bulbs). :) Another topic that exposes the ignorance of people answering...

żarówka rtęciowa · Answer

A light bulb connected to a voltage twice lower than the rated one consumes about 3 times less power. Thus, by connecting two series-connected 230V 200W bulbs to 230V, they will have a total power of approx. 140-150W.

jony · Answer

Hello.
We have U=1000V=1KV; I=5mA, so we have R=200K/5W

We instead of this resistor R=200K/5W give two resistors of 100K/2.5W connected in series .
Now let's calculate the power dissipated in these resistors
P=U*I
The voltage across the 100K resistors will be 500V (the voltage has dropped to half), i.e. the power that will be released on the series-connected resistors
this P=500V*5mA=2.5W so we can pull the resistors 2.5W 100K connected in series instead of one 200K/5W

Anonymous · Answer

Why am I posting links? staszek sorry for the mistake, the power then takes the value of half of one resistor (in series it will be 0.25W) I generalized very much that's why I sent the link cms and in what system did you connect these resistors?, what power flows through these resistors? I am not a fairy, please provide more information they will not light up at all

pmxxyz · Answer

They will, but only slightly... :wink: Unless we attach them to a source with a voltage of 2 * 230 = 460V. Then two hundreds will give 200W.

CMS · Answer

well, the barrage is not the best example resistors work in the cd rom power supply in the car. the power that is deposited on them is exactly 5 watts

szod · Answer

tridio - read what I wrote and then count yourself. I'll give you an example and make it easier. Take a 100Ω resistor and two 50Ω in series. This 100Ω at 10V will dissipate 1W of power. With two connected in series, the voltage will divide in half for each and will be on each 5V, so each will dissipate 0.5W. So with series connected resistors you will be he had to increase the voltage twice to get 1W of power on each resistor. Meaning that for example, instead of one 1W 100Ω resistor, you can put two 0.5W 50Ω resistors in series. It will be the same. Of course, we are talking about an equal division of resistance and I write about it all the time. Sorry, I can't explain it more simply.

Anonymous · Answer

szod if you give 2 resistors (in series) 50Ω 0.5W, you achieve as much as one 100Ω 1W? I just see how the electrode falls (yes you will get 100Ω but 0.25W)

Aleksander_01 · Answer

I think it's going down too. In which county do they teach electrical engineering like this?

Anonymous · Answer

aleksander_01 what about me? :D Added after 34 : you mean i'm ignorant?

Aleksander_01 · Answer

Yes, I wrote about you. So tell me the district where they teach that. Do you have knowledge gaps? Oh and it's big - read and understand your post 21;13

Anonymous · Answer

I don't understand where did I go wrong can you explain me? Added after 1 [minutes]: are these watts? should it be 0.5?

szod · Answer

tridio - You really don't understand what I'm writing. Oh well. I would devote myself I'd draw it for you, but I don't have anything at the moment. So take a piece of paper and yourself draw how the voltages and powers will be distributed. You can insert a drawing here. Now explain to everyone exactly step by step how you calculated that 2 times 50Ω 0.5W in series will give 100Ω 0.25W? Well well. With this line of reasoning, now tell me what the total power of the resistor set will be 10 pieces 10Ω 0.1W in series?

Anonymous · Answer

I apologize to everyone here, I already know what the mistake was (power with serial), I don't even know why I wrote it and I insisted on it. Sorry again

RadekB86 · Answer

I've been reading your posts for so long and I don't understand anything anymore
1) when are powers added? in series or in parallel?

And so to the point, I have such a trivial problem with this power, in my store they sell 2.2KΩ 0.25W resistors, unfortunately I need 2.2KΩ but 1W, and they only have quarters.
I thought that I could give 4 resistors of 0.25W each and it would be 1W in total
but unfortunately I need to know how to connect them to know the resistance of these 4 resistors. Please help. Thanks in advance!!

Aleksander_01 · Answer

Hello. Connect as shown in the picture.

RadekB86 · Answer

Aha, so the conclusion from the fact that in series and parallel powers are added?

żarówka rtęciowa · Answer

Exactly. Often, for service purposes, the RA, RAC, RDCO resistor was replaced with several less powerful resistors. Series connection is also used in high-voltage circuits because of the high price of high-voltage resistors.

emka371 · Answer

Hello!
The powers dissipated on the resistors always add up regardless of the connection (serial or parallel). However, as for their nominal power (i.e. the maximum power that can be dissipated on the resistor), the matter is more complicated. If they are resistors of the same power and resistance, then regardless of the connection method, the nominal power of the system is the sum of the powers of individual resistors. With different values of resistance or power of resistors, their maximum power should be calculated - simply one of the resistors will exceed its maximum power earlier than the other.

Pegelmesser · Answer

I read this discussion and the knife opens in my pocket ... such things happened in elementary school in physics. Shame people!!

ffff · Answer

gentlemen, no regrets, but that the rez powers are added regardless of the connection, even I know it (Łaśic).

Pegelmesser · Answer

Yes, but it's an addition like: 2 cars + 3 bikes = how many motorcycles? It's not about adding up the power, it's about determining the power distribution!

Can I Replace a 0.5W Resistor With Two 0.25W Resistors in Series or Parallel?

Can I replace a 0.5W resistor with two 0.25W resistors in series or parallel, and how do resistance and power ratings combine?

Topic summary

FAQ

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