Adding Ohm symbol to schematic

Joke: How did the detective know the kidnapper was an EE? Because in the ransom demand he asked for 564 bucks instead of ½ million. (Next higher value in E12 series.) :rofl:

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I think you are a chip off the old wafer. I should now go a wafer a while.

For “typing” special characters I use one of these (repurposed) trustmaster mfd’s. Each button can execute some script in the supplied software. (For example keypresses)
The inner window can contain some graphics or text to describe the action.

168_medium

I find them well build.

For “typing” unicode characters, I found this useful:

First create a registry value under key HKEY_CURRENT_USER\Control Panel\Input Method of type REG_SZ called EnableHexNumpad, set its value to 1, and reboot. Then you can enter Unicode symbols by holding down the Alt key and typing the plus sign on the numeric keypad followed by the character value. When you release the Alt key, the symbol will appear. This approach worked with most applications I tried, including Firefox and Safari, but did not with Internet Explorer.

I truly have no idea what that is. I am probably not the only one on this forum. Looks like an IC socket, but Mfd is a term for microfarad. I googled it and found “Thrustmaster mfd” on Amazon. Looks like maybe something for an aircraft simulator? Some explanation might enlighten or entertain many of us (or maybe just me?)

It’s indeed a UI element out of an airplane. Warthog 10A I believe. Except the screen/lcd it would interact with. That window can be used to place a sheet of paper in. This gives 24 buttons per mfd (usb) to configure.
The software can switch between different configs, so it can be used to simplify all kind of repetitive tasks (keystrokes, run applications).
I use it mostly when calculating with units and superscript numbers (²)

MFD = Multi Function Display
A fancy term for what most modern equipment does these days, a smartphone is a good example

Thanks. That is particularly helpful. @HendriXML still left me with 22 buttons per microfarad. That is not much better than peanuts per ohm.

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https://github.com/HendriXML/KiCad-BOM-reporter/wiki/Screenshots

I use the above. One report sorts on numerical value (not formatted text). The location report, groups the bomitems on storage location, which in case of my stacked sorting boxes speeds up collecting of components a lot.

So where and how do you enter the numerical value?

I am thinking back…way back…at a job I had in 1980. We had access to a database of components in our system. The case that comes to mind is a 1 uF capacitor. I do not think that a mu symbol was available. Here is a list of the sort of mutually exclusive listings I could find for such a capacitor:

1uF, 1 uF, 1.0uF, 1.0 uF, 1 mfd, 1mfd, 1.0mfd, 1.0 mfd. There might have been 1u, 1.0u, 1 u. and 1.0 u also. I am not saying that I encountered all of those permutations but I did encounter many of them. It was a “willy nilly” dependence upon the preference of the person who entered the information into the database. The result was that it was very difficult to find components in the database.

I don’t doubt that there are other ways around this issue. But I have no programming skill, and I do not understand what you are doing with a screenshot at github. Years ago I tried to use git for KiCad version control, and I decided that github was much more complicated than KiCad and gave up with that. But my numerical values will simply copy paste into a spreadsheet and (most of the time) be interpreted as numbers. No programming required.

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The values can indeed be entered in multiple ways but are in my bom reporter parsed and placed in binary coded decimals (32) with a floating point and an unit indication. (Thus also “normalizing” the values)
Using the correct techniques this parsing is not so difficult, but most of the time results in lots of code.
These bcd values can then be compared between each other, like whether they’re on stock. (Main function of the scripts)
When converting back to strings which prefixes are used can be choosen for each unit in a single function.
No mF for example. The same tool I also use for calculating “circuit values”, which are then reported in a designator BOM report for verification. In those calculations I need some 10+ special unicode characters regularly, so the mfd keeps it user friendly.
To bad my electronics skills don`t match with the level of automation. :wink:

FWIW I have found Quantiphy useful in this area. It does unit normalisation nicely in python.

https://quantiphy.readthedocs.io/en/stable/

I took a look at those classes out of interest.

Some differences: in my scripting environment units can be defined as native elements (not strings) with equivalents.

https://github.com/HendriXML/KiCad-BOM-reporter/blob/master/Script.Common.Science/SiUnits.xml

This result in the following benefits:

  • calculating with/resulting in compound units like m/s
  • understanding equivalent units regarding the base units, like V/A can be added to Ω.

Also text (decimal numbers) to float (used in those classes) is not always lossless, so in that case rounding a float is needed to get to the same text (decimals).
That’s why my tool needed to support both. One for lossless “storage”, one for calculating. The calculations in my tool also keep track of uncertainty (significant digits), which can be used in displaying numbers.

I found that F# (programming language) also has native unit support.

Also Google search calculation has some unit support.
https://www.google.com/search?q=%3D1+V+%2F+3+A+*+4+A%5E2

Thinking about this stuff again reminded me of a fun fact when calculating with units:
The unit of mass is not g, but kg.
As shown by google in calculating kinetic energy.
https://www.google.com/search?q=%3D+1%2F2++2+kg++%281+m%2Fs%29%5E2
There’s no μkg though (that would be mg), so that exception alone makes it hard to treat units as “unidentified” strings and separate from prefixes and still do calculations in the right way.

I think that is a matter of CGS versus MKS systems. In CGS, a gram is certainly a unit of mass. I think there is less ambiguity in electronics. I stick to the base units; ohms, farads, and henries (unless your name is steve.) I make no claims to my method being good for related disciplines such as physics or mechanical engineering.

And isn’t mg either magnesium or an old English sports car? :smile:

I don’t think any of those are base units :wink:
https://en.m.wikipedia.org/wiki/SI_base_unit

Joke for the CGS folk:

“Erg!”

“Stop complaining! It’s only a tiny amount of work.”

:wink:

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:grinning: I remember learning about ergs many years ago…it might have been in some nuclear physics book…

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I started electronics by ripping old stuff apart. I remember caps where the value was written in “cm”. 1cm was about 1 pF.
On US schematics bigger caps where written as MMF (mili-mili-farad).

Die Text-Ersetzung ist eine brandneue Funktion von KiCad 6.

Mit der Text-Ersetzung können Sie eine Variable erstellen, die beliebigen Text enthält, und diesen Text überall im Schaltplan anzeigen, wo Text erscheinen kann.

Die neue Textersetzungsfunktion ist überall verfügbar.
Hier ist eine kurze Demonstration, wie dies funktioniert.

Zuerst können Sie Ihre Textvariablen im Bereich Textvariablen unter der Projektgruppierung des Dialogfelds Schaltplan einrichten definieren.

Ein Beispiel sehen Sie in meinem Screenshot 1. Dort folgen Sie der Nummerierung. Klicken Sie im Eeschema auf Datei/Schaltplan einrichten…
Weiter geht es im Projekt/Textvariablen, ein Klick auf Plus und den name_of_variable so wie
die Übersetzung eingeben.
Erstellen Sie als Nächstes etwas wie ein Widerstand Bild2 und öffnen mit “E” die Einstellung. Um den Wert der Textvariablen anzuzeigen, verwenden Sie die Notation „${name_of_variable}“.

Das Ergebnis ist, dass KiCad alle Vorkommen aller Variablenplatzhalter durch den Wert der Variablen ersetzt, wie im Bild4 zu sehen.

Sie können auch Syntaxkonventionen verwenden, um zu steuern, wie der Text aussieht. Es gibt ein praktisches Syntaxhilfefenster mit weiteren Informationen.


Variablen2

Variablen4
Uploading: Variablen1.png…

It’s interesting to note that the usual shorthand for discrete RCL component values, we do include the SI unit symbol for capacitors and inductors. It’s only for resistors that we omit the symbol and use a unit less number.

0.1uF
4.7uH
2.2K