Fen Logic Ltd. Electrocalc
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Electrocalc is a program to help with the most common electronic calculations. If you are just like me you know most electronic formulae by heart. And when using Ohms law the formula V=IxR is easily converted to R=V/I or I=V/R.
But how about Vt=Vo(1-e^(-t/(RC)))? Isolating C is a bit more difficult. Next you have to select the nearest R and C from the E12 or E24 range and then calculations start again to find the actual t or Vt with the chosen R and C values.
Electrocalc is a great help with that. You select the variable you need, fill in the others and the answer comes out.
It has formulae for:
As with all my GUI programs, the code consists of a small excutable but requires some big QT4 dlls to run. (See also the
bottom of this page). This is the electrocalc.exe code, there is also a zip version.
These are the QT4 dlls (4.8Mbytes) in zipped format only.

Ratio:
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Ratio is a program to find the optimal component choice. For example you need a voltage divider with an input/output ratio of 0.63. But which two resistor values get you closest? (The answer by the way is 330 and 560 from the E12 series or 300 and 510 from the E24 series)
Besides the most common formulae you can enter your own expression which will then be searched for an optimal solution. (Which may take a while...)
The main features:
As with all my GUI programs, the code consists of a small excutable but requires some big QT4 dlls to run. (See also the
bottom of this page). This is the ratio.exe code, there is also a zip version.
These are the QT4 dlls (4.8Mbytes) in zipped format only.

PICT2ASC:
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PICT2ASC is a program to convert images to PadsⒸ ASC format so they can be placed on a PCB.
For example this one: Picture comes out on a PCB like this: Picture
The main features:
As with all my GUI programs, the code consists of a small excutable but requires some big QT4 dlls to run. (See also the
bottom of this page). This is the pict2asc.exe code, there is also a zip version.
These are the QT4 dlls (4.8Mbytes) in zipped format only.
This program requires additional dlls for handling all the various graphic format files.
imageformat dlls (325Kbytes) in zipped format only.

Caveat Emptor: (or in plain English: Beware!)
All these programs are free. They come with no warranty as each will tell you in their help file. If you want extra features I am willing to listen but limited in time so it may take a whil.e (Or I may plainly reject you request.) Of course throwing money in my direction might help ☺.

Download
These program consists of an executable and QT4 dlls. The program will definitely work if you place it alongside the dlls in a directory. If you use only one program that is fine. However if you use multiple programs it saves disk space if you place the dlls once in a central place instead of copying them over-and-over again. The place I would recommend is to place them in: C:\Windows\System32\
Some programs require extra dlls, to do with handling various graphic file formats. See the download instructions of each program for that.