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Would using a thicker cable like 16 AWG affect the signal being received from an RFID or Ultrasonic sensor?

I understand AWG can make a significant impact on voltage when a thick cable is used over a long distance. In my head signal data is delicate so a nice thin wire will ensure little disturbance....

Looked around and couldn't find a clear answer so hopefully someone can help!

  • you asked the same question twice ... yes, wire size does affect the signal ... whether the actual data is affected depends on the type of data, analog or digital ...... nice thin wire will ensure little disturbance most of the signal will be absorbed by the wire – jsotola Oct 29 at 1:57
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    I don't think thickness matters. The problem is that a long wire acts like an antenna, picking up external "noise", that can influence your signal. This is mostly an issue for analog signals, or really fast digital signals. – Gerben Oct 29 at 16:33
  • I use 30AWG wire for Arduino signals. I never had any problems with those wires. And to be precise I use silicon wires which are extremely flexible - perfect. – Edgar Oct 31 at 4:00
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A signal is just a varying voltage. A wire is just a (very long) small resistor. The device reading the signal is just a current sink.

That's three terms there: voltage, resistance, and current. Three terms you should know are related by Ohm's Law.

Also, some simple rules:

  • The thinner the wire the bigger the resistance
  • The longer the wire the bigger the resistance
  • The more load on the wire the greater the current

And of course, that all means:

  • The greater the resistance or the greater the current, the greater the voltage drop across the wire.

If the voltage drop gets too great then the device receiving the signal won't be able to work out what it is.

But then of course a wire is also an antenna picking up all sorts of noise. The longer the wire the more noise it will pick up. And the thinner the wire the greater the resistance and the greater the resultant voltage drop, meaning the lower the noise margin and immunity.

So no, a thinner wire isn't better than a thicker wire. The exact opposite is true.

  • There are also things like it has some self inductance and capacitance which acts against changes. And of course there is signal crosstalk caused by it. Also there should be matching impedance on both ends, so there are no signal reflections. – KIIV Oct 29 at 14:53
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    Yes, but none of that really has anything much to do with the thickness of the wire. I could have gone into signalling methods, voltage levels, NRZ, differential signals, shielding, etc... but all that is outside of the scope. Maybe if the question was asked on the EE.SE, but not here. – Majenko Oct 29 at 14:54
  • True. Maybe skin effect, but it'll be on higher frequencies than low speed serial or pulses from ultrasonic sensor. – KIIV Oct 29 at 15:00
  • I'd put the last line in bold to make it easy on skimmers. – chicks Oct 30 at 21:43
  • Of course at high frequencies the problem gets a lot more complicated. As you say, most of that doesn't have much to do with wire thickness, but I would make that the major point of the answer: "As long as your wire is thick enough to limit the voltage drop so that you have good signal to noise, wire thickness is much less important than a whole range of other factors: Inductance, capacitance, RF shielding, etc etc." – Duncan C Oct 30 at 23:46

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