# Is this network of resistors in series and parallel, the way I intended?

https://www.circuitlab.com/circuit/gu5zh6pdvj8q/parallel-and-series-question-circuit/

simulate this circuit – Schematic created using CircuitLab

Do these circuit schematics accurately represent these other 2 circuit schematics, which I made using Tinkercad?

If so, is the resistor network for C2 built to match the equation

1/(1/(330 + 330 + 330 + 220) + 1/(330 + 330 + 330 + 100))

Which represents one serial circuit with a combined value of 1110 ohms, and another of a combined value of 1090 ohms, both in parallel, which should give a combined ohm value at the output of the circuit of 570 ohms?

If yes, how come my multimeter reads 500 ohms at the beginning and the end of these resistor networks?

EDIT:

Solved, the 400/500 ohms is because of the tolerance.

• You have one long series chain starting at A30 and ending at C29. Mar 24 '20 at 12:40
• @Majenko How come? The resistor at A30 is not connected to the network starting from c29? And ar ethen added in parallel at 13? Mar 24 '20 at 12:44
• A30-|===|-A26-B26-|===|-B22-A22-|===|-A18-B18-|===|-B13-D13-|===|-D17-E17-|===|-E21-D21-|===|-D25-C25-|===|-C29 Mar 24 '20 at 12:47
• 560 ohm and 10 ohm are common values so why all the drama? Mar 24 '20 at 12:51
• Until you have something connecting A30 and C29 (like you have done for the column 13) you won't have anything in parallel. Mar 24 '20 at 12:57

## 2 Answers

You yet have to connect Line 29 with Line 30.
Then your curcuit represents your formula.

• Thank you for you answer, Could I possibly ask you to draw the schematics for it aswell, so I can understand how the schematics relate to real life better? Mar 24 '20 at 12:50
• @GeorgeWTrump, much better if you draw the schematics yourself, then you'll really understand properly. The schematic editor here is a breeze to use. Mar 24 '20 at 12:57
• @TonyM Well I gave it a go at that, and made my own diagrams. I have added them to the edited question. Perhaps you could take a look at it? Mar 24 '20 at 13:31
• @GeorgeWTrump, thanks for putting the work in. It needs to be visible in your question rather than as a link. Readers need to see it in front of them and links can break anyway. Please can you make that edit. Mar 24 '20 at 14:08

Resistor value

What is the resistor value 570 ohm for? Does it really matter if it is that precise? If 550 ohm would suffice, just add a 330 and 220 ohm resistor to get 550 ohm.

Note that each resistor has an accuracy so probably with two 5% precision resistors you get away with 550 ohms.

Breadboard

To put this on a breadboard, place one resistor from e.g. a30 to a26, and than on the same vertical line, starting at e.g. b26 to b22 the second resistor. Now you have the resistor in series.

To put two resistor in parallel, place two resistors with both ends on the same vertical lines, e.g. one from a30 to a26 and the second from b30 to b26.

• Right, Tinkercad wouldn't allow me to change the size of the resistor, but in reality the last 220 and 110 ohm resistors are in parallel, with both sites sharing nodes. Also, it was not only because of me needing a 570 ohm resistor value, I also wanted to challenge myself and learn more about resistor networks. Edit: Oh wait, the last resistors are only connected with one end. I will try to change that. Mar 24 '20 at 12:47
• Also you can create the two series subcircuits on each end (so one below the split line between e an f, and the other above), and than connect the most left ends together and most right ends (to make both series into a parallel configuration). Mar 24 '20 at 12:53
• Well, that would be a possibility, but the schematics I made is not for the whole circuit, only the part with resistors. In real life the other part is filled with a potentiometer and a LED 8x8 matrix. But thanks for the suggestion anyways, it has given me a new tool in the future :) Mar 24 '20 at 13:01
• Yeah, I usually use CircuitMaker for making the circuits in the first place. I just couldn't figure out how to translate the other way around. But I have tried to make some diagrams, perhaps I could ask you to take a look at them? Mar 24 '20 at 13:34
• It seems 400 ohm is strange (I didn't check all color codes of the resistors). However, you should measure each series (disconnect the other), to rule out which string is ok, than check each resistor separately (while breaking the rest of the circuit). Mar 24 '20 at 14:20