Yet another resistor calculator - Page 1
Forum section: electronics / beginners

author: wizeia
author_rank: Newbie
timestamp: May 11, 2025, 06:00:25 pm
content: How hard is it to obtain a resistor value ? I mean... finding the value is probably the easy part, matching it with the values you have on your drawer is the complicated part.I have more than 20 years of developing electronic boards. In the first years I used an excel sheet, which was far from practical. Then I've transformed it into a script, and that what I used for more than 15 years.I've shared that with some friends, and the feedback was very positive. So, I've recently transformed it into a website called Wizeia.https://wizeia.com/It calculates any kind of circuit you can think of. You need only to enter the formula and the conditions you have. Try it out and let me know what you think.I hope you will find it useful.

author: xvr
author_rank: Frequent Contributor
timestamp: May 12, 2025, 12:13:15 pm
content: Very interesting tool. Just two wishes:Add the selected net's schematic to the main page. These schematics are available on the 'Circuits' page, but it's quite cumbersome to switch back and forth to see what the symbols of equations meanAdd resistor tolerance to the estimate. Example: there's no point in creating a 10.001M resistor network - the resistor tolerance will screw up 0.001 of it, but that's not clear from the output. The script will successfully create a 10M + 1K network, without any comment about it being useless. If it says you'll actually get something between 9.9M and 10.1M, that might help a lot.

author: mariush
author_rank: Super Contributor
timestamp: May 12, 2025, 12:33:04 pm
content: Ridiculous to have to accept terms and conditions to use a tool.I'd rather have radio buttons instead of drop down list for the EIA subsets, or even better, to be able to check several of them, for example EIA12-E48.Most computer screens are big enough to support having the Use case as a list on the side of the form, instead of a drop down list.Consider having a drop down list if the user uses a phone (you can use css rules to hide or show form items or controls) and a side list if the browser page width is big enough.On a standard 1920x1080 screen, I'd expect the form to fit fully on the page ... now the Solve button is clipped if using a browser. I'd also expect after hitting the Solve button to have the form scroll down and get the results list in focus. Now, you click and nothing is visible on the page, only after one scrolls down you get something

author: BILLPOD
author_rank: Frequent Contributor
timestamp: May 12, 2025, 12:35:39 pm
content: Thank you Wizeia, One can't have too many tools for this job. How did you go so long before discovering EEVblog Forum?

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: May 12, 2025, 03:32:47 pm
content: I often use the Spice modelling software “Tina” to work out resistive dividers, etc. While we can all (eventually) calculate combinations of resistors, drawing the partial circuit and letting the Spice software work out the Voltages, currents, etc. is very easy.

author: tooki
author_rank: Super Contributor
timestamp: May 12, 2025, 09:46:54 pm
content: Quote from: wizeia on May 11, 2025, 06:00:25 pmThat’s rather clever, and the circuit diagrams are nice and clear. I agree that it’d be nice to have them shown side by side. There’s plenty of room, no need for such gigantic controls.The only outright error I found was with the LED calculation terminology. It’s not “polarization” nor “biasing”. It’s “LED current limiting”, and the current through the LED is If, not Ibias.Also, there’s some inconsistency in the schematics as to voltage sources: in some, you use the battery symbol, in others a voltage source.