# Resistor

Design using CAD.

### Designing Resistor using Google SketchUp.

The first step is to find out the datasheet of the component you wish to make so that you know exact dimensions.

The datasheet that i have used to build the resistor in available here.

CRF-12 means it is 1/8th of a watt (12 x 8 = 100)

We will choose CFR-25 as we want to design a quarter watt resistor

So the dimensions that we need are: L = 7.0 mm, diameter of edge caps = 2.5 mm, diameter of the wire = 0.5 mm

Plan:

We will create a 2D shape equivalent to the vertical cross section of the resistor and then again dividing it into half vertically.

it should look something like this...

A close up of one side of that is ... Notice that we have taken the dimensions as very big values so that we can work on it easily. Some students have found it very challenging to work with real dimensions so a scale of x100 is suitable for small objects.

Once we are finished with the drawing we can always scale it down using the scale tool.

But before scaling, make to sure to select all using "Ctrl+a"

Also you can leave scaling to the end. Finish the model and have a 3D version and then scale.

Also, it is a very good idea to use a graph paper to design the 2D structure.

Now we will use the "Follow me" tool to rotate this 2D drawing through 180 degrees

First select the circle using the "Select tool"

Now choose the "Follow me " tool and click on the section closest to the circle

This will convert the bottom section into 3D

Again select the circle using the "Select tool"

...and click on the next section

...to convert it into 3D

Note the raised edge for the band color is still 2D

Do the same for that part also

raised band is also in 3D now

another view (zoomed out)

repeat the process for all parts and you will get something like this...

Close up of one end of that is ...

Let us render it using paint bucket tool.

Time to insert wire leads

Resize it to the actual size you want and we are done.