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Beginner question.

I was reading about "resistors in series".

https://www.electronics-tutorials.ws/resistor/res_3.html

Perhaps naively I thought it would be possible to go buy a component which is already a series of resistors, but such a product does not exist.

Why is this?

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    \$\begingroup\$ Are you looking for resistor networks? \$\endgroup\$
    – Hearth
    Sep 4, 2020 at 23:32
  • \$\begingroup\$ I'm not sure I quite understand. What would be the difference between resistors in series and a larger resistor? Do you want access to the points in-between the resistors in series? \$\endgroup\$ Sep 4, 2020 at 23:40
  • \$\begingroup\$ Yeah it seems like you’re describing resistor networks although if you’re just getting into electronics I would recommend a solderless bead board and individual resistors.. \$\endgroup\$ Sep 4, 2020 at 23:40
  • \$\begingroup\$ a potentiometer \$\endgroup\$
    – jsotola
    Sep 5, 2020 at 1:05
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    \$\begingroup\$ Buying resistors in series is like buying ropes knotted together, or trailers attached to trucks -- it's theoretically possible, and you can even envision it, but in general you buy the individual pieces separately and then put them together yourself. \$\endgroup\$
    – TimWescott
    Sep 5, 2020 at 2:32

2 Answers 2

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There is nothing in the referenced website that would indicate that "resistors in series" is a component in itself. Why would you need to buy such a component when you can easily do it yourself with much more flexibility than any supplier could offer. Just look at the possibilities in purchasing a single resistor. Between the resistance value, power handling capability, tolerance, temperature range, etc. there are literally thousands of different resistors. It is hard enough for a distributor to stock even a fraction of the available resistors. How would they be able to handle resistors in series. The possible combinations would literally run into the millions.In any case, it is actually rare in actual circuit design to have even 2 resistors in series. Usually a designer can choose a single resistor to handle his requirements. In unusual circumstances such as when a particular resistance value is required that is not a standard value or a single resistor cannot handle the power or voltage requirements, then series resistors are used.

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For fixed resistance values, there's not much reason to. You can buy two resistors and put them in series very easily -- they take up very little space on a circuit board. You can also buy resistors of many, many different values off the shelf. Check out this DigiKey search link, where there are hundreds of different resistances available between 0.1Ω and 10MΩ. And that's just for 1% tolerance, 1/16W, in an 0403 package!

If you actually need series resistors, it's probably going to be because you need a connection between the resistors. [EDIT: Or some more application-specific considerations as mentioned in the comments.] (The voltage divider section in your link talks about this.) For logistical reasons, it's usually better to use two separate resistors. But if you need a lot of in-between connections, or you need the resistors to be matched, you can buy them in a single IC. You might still have to make the connections on the board.

If you need a variable resistance, you can use a potentiometers, which is basically an adjustable voltage divider.

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    \$\begingroup\$ I didn't mark you down, but there's also high voltage tolerance, dissipation, mitigating single-point failure concerns, and I'm sure others that will come to mind after I post this. It's not just for the connection between. \$\endgroup\$
    – jonk
    Sep 5, 2020 at 1:35

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