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Can someone tell what is the meaning of the circled item in Simetrix for a resistor?

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Freshman
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  • @MarcusMüller I should look around before answering, That answer is far more comprehensive! Or maybe I should wait till I have more time lol – MCG Jun 19 '23 at 08:46
  • @MarcusMüller, can you tell why is it relevant in a simulation? – Freshman Jun 19 '23 at 11:38
  • @Freshman, I am not 100% sure but, it seems E12 series will have better tolerance than E6. Similarly, E24 tolerance will be better than E12. Is your simulator going to use this tolerance information and tell you how much your circuit output can vary due to this tolerance? – sai Jun 19 '23 at 12:24

1 Answers1

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These are standard resistor series. Each E series has slightly different values in them. There are more than just these shown, in fact, there is E3, E6, E12, E24, E48 & E96

The number tells you how many values there are in each decade. So E3 will have 3 values per decade and E48 will have 48. Usually, the lower the number, the lower the tolerance range too.

The standard EIA values in a table can be found HERE, along with an explanation.

MCG
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  • Thank you for the answer. Can you tell how is it relevant in a simulation? – Freshman Jun 19 '23 at 11:39
  • Irrelevant. The relevant part is the resistor value – MCG Jun 19 '23 at 12:00
  • Ok. Thank you for confirming the E series value is irrelevant for the simulation – Freshman Jun 19 '23 at 12:16
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    @Freshman that's not what MCG said. The resistor value will be chosen from the E-series you select. – Marcus Müller Jun 19 '23 at 12:50
  • Yes, perhaps I should have been clearer. The E series value doesn't make a difference to the simulator. 1k will be 1k. However, when selecting a resistor value, using the E6 series will give you significantly less choice. So the E series is irrelevant to the way the simulator will simulate the circuit, but it is relevant for selecting a value. – MCG Jun 19 '23 at 14:08
  • Can you please explain what you mean by "will give you significantly less choice" ? – Freshman Jun 19 '23 at 14:54
  • @Freshman If you chose E6, and stick with the 1k decade, you will have choice of: 1k, 1.5k, 2.2k, 3.3k, 4.7k & 6.8k. If you selected E12, you'd get 1k, 1.2k, 1.5k, 1.8k, 2.2k, 2.7k, 3.3k, 3.9k, 4.7k, 5.6k, 6.8k & 8.2k. Your choice of values have doubled. That's the significance of the E value, as described in the link from my answer. But choosing 1k in E6 makes no difference to the simulator as a 1k from the E12 series – MCG Jun 19 '23 at 15:00