# The First Transistor (Teaching Model)

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### Didactic model of the "first transistor".

In this project the models such as constructing a didactic model of the first transistor for which I made use of the materials that can be easily obtained, in addition to a little painting, the prototype / model I did on a scale a little larger than the original.

But from before, a bit of history.

It all started at Bell Labs, where American physicists Jhon Bardeen, Walter Houser Brattain, and William Shockley conducted experiments and observations to try to create a solid-state amplifier, making use of the properties of semiconductor materials, thus replacing the Vacuum used at that time.

The above image shows the first transistor created at Bell Labs in Murray Hill, New Jersey, United States in 1947.

Its inventors won the Nobel Prize in Physics in 1956 for "their research on semiconductors, and the discovery of the transistor effect." Now we continue with the instructions to build our didactic model. Then we will explain its operation and its use today.

### Teacher Notes

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## Step 1: Materials / Tools.

To facilitate the construction of the PT (first transistor) we will make use of 3D printing.

Tools:

• White liquid glue (Resistol)
• Instant glue and baking soda
• Brush
• Tongs
• Screwdriver, flat or cross (depending on your screws)
• Large Scissors
• Soldering iron and tin
• Cutter
• Fine scissors

Materials:

• Pieces printed in 3D
• Clips
• 15 cm UTP cable
• A can of juice or soda
• Aluminum foil
• A thin piece of cardboard
• Acrylic paints (gold and silver)
• 3 screws M3 of 10 mm
• Paper sheet
• Piece of wood 10x10 (thickness of your preference)

## Step 2: Preparations for Connection Triangle.

To begin with our piece of cardboard we'll make a small abstract figure, resembling broken piece of metal, little enough to fit on the underside of our baseline context. And we painted it in silver along with our triangular piece printed in 3D.

* Note: it is preferable if the triangular piece is printed or is based on the black color so as to have a finish on the paint that is uneven to resemble a piece of used plastic.

If necessary, also review the painting on the piece of cardboard, as many times as necessary until it has the appearance of a metal.

## Step 3: Construction of the Triangle of Connections.

On the sheet of paper, we are going to make a strip in the width of 5 mm, with which we will simulate a small sheet of gold, used in the connections of the transistor. As you have to imagine, we will paint it with gold paint.

* Note: it is not necessary to paint the whole strip, only about 3 to 4 cm (30-40 mm). If it is possible to get a gold leaf, it will save you the trouble of painting it.

Once the gold strip and the plastic triangle have dried we will proceed to join them.

As seen in the image, the strip divided into two parts is attached (with liquid glue) to the equal sides of our isosceles triangle, making sure that at the tip there is a very small gap between the two parts of our strip, and in the Extremes by cutting the excess of it.

* Tip: To make it easier for you to glue the strip to the plastic triangle, lean on a thin or flat tip brush.

By using a UTP cable, we will make the two protruding contacts of our triangle. At one end of our cable we will peel 5mm of the same and we will cut it to 3cm. We will also peel 5mm from the end that has not been peeled. This procedure we will do twice.

* Note: make sure that the piece of cable used is of a dark color (gray, black, navy blue or brown).

The next thing is to heat the soldering iron to tin one end of our pieces of wire.

* Tip: You can help the tweezers to hold the small piece of cable.

To join our pieces of wire to the plastic triangle we will need instant glue, we will glue them from the end that is not tinned.

## Step 4: Spring Construction.

We will begin by painting our cylindrical piece of plastic in silver.

Then we will unfold our clip so that supported with our tipped tweezers we give the shape that you can observe in the image. Once we have already folded the clip, we will join it with our plastic cylinder using instant glue and baking soda, trying to form a kind of mountain.

When the glue has dried, we proceed by painting the small mountain of glue we made with silver.

## Step 5: Preparation of the Assembly Frame.

With the M3 screws we will go over the holes in our plastic piece (frame).

We take our can and trim it to get a rectangle or a large piece of it. From it we are going to cut three rectangles of 1cm x 1.5cm.

* Note: It is advisable to use a paper or a sheet to not stain our work surface.

With a fine sandpaper, we will remove the paint from the outer side of the rectangles we cut.

Use the scissors to round the ends of the rectangles.

Using a screwdriver or something with a thin point, we will make a hole in one end of the aluminum rectangle, large enough for the screws to pass.

Now place the aluminum rectangles with the M3 screws in the frame.

Then take the piece of aluminum and bend it to form a strip a little larger than the thickness of the frame, trim it to occupy the inner base of the frame and paste it with instant glue or white glue.

* Note: the part that protrudes slightly from foil, we must fold it downwards, covering the edges of the inner base of the frame

## Step 6: Assembling.

We take our cylinder with the spring and mount it in our triangle of connections as follows:

The other end of the spring is to be inserted into the hole in the top of the frame, ensuring that the spring acts as a pressure on the opposite side (the inner base).

Once observed the point where the tip of our triangle is supported, we will take our piece to paste, either with white or instant glue, the piece of cardboard with abstract shape that we painted in silver. And we will return to place our spring with the triangle of connections, this time supported our piece of cardboard.

* Note: both the spring support and the connection triangle are Simply assembled (without glue) with the purpose of being able to disassemble them to be able to observe them more in detail.

## Step 7: Connections to Terminals.

To make these connections, we will need another piece of a wire from our UTP cable, which we will try to peel 4cm to leave the copper that is inside exposed.

Cut to 4cm our copper exposed, and we tin a tip, this process we must do it twice for the connections that go to our triangle.

Once we have tinned our small copper wire, we will weld it to one of the ends of the connecting cable of our triangle.

* Note: if it is possible to leave a large amount of solder in the connection will have a better aesthetic result compared to the original.

At the other end of our copper wire we will give the shape of a hook, which we will position in the screw of the corresponding side. Now we would only lack a base in which to position our didactic model (optional).

## Step 8: Base for the Model (optional).

In this case, the base I will use is a piece of MDF wood of 10cm x 10cm (the thickness does not matter), in my case the thickness of the wood I used is 2cm.

In order not to leave the wood of the same color I decided to paint it with black spray (optional).

To finish, all that would be missing would be to stick our frame in the base of wood with resistol or instant glue.

If desired, a triptych or a small information sheet containing the data of the first transistor can be printed.

This concludes the construction of the project.

But before we finish completely, let's look at a small explanation of how it works.

## Step 9: Explanation of Operation and Current Uses.

As we can see, our transistor has 3 connection terminals (input signal (-), input of positive charges (+, as far as germanium), and amplified signal output (-)). The first transistor fulfilled its purpose of amplifying the signals that thanks to semiconductor materials, such as silicon and germanium (in this case, germanium) was possible. The transistor is a device that is controlled with current and from it is obtained amplified current. For this reason it considers an active component, not as the resistors or capacitors that are considered as passive components, since these components do not require current to be controlled.

It has this triangular shape, since the signal input and output connections must be close together (at the tip of the triangle) and in direct contact with the germanium in order to obtain the amplification effect of the signal. From this invention, it has been improving more and more, both in operation and in its size, making it smaller and with more uses (besides the amplification) as: Oscillator, Switch or Rectifier. As for the size, which began with the model we have recreated, which fits in the hand, to reach a processor of 37.5 x 37.5 mm, containing 731 million transistors inside. The transistor was the invention of the century and was what revolutionized the world. So great was this invention that it was possible for man to reach the moon, and to form the world as we know it now.

To know a little more about the subject, I leave you a documentary of the history of the invention of the first transistor.

Needless to say, I hope and you have enjoyed the instructable, and you have understood the operation and importance of this great invention. Comment if you liked and share the photos of your didactic model of the First Transistor if you have done this project, and do not forget, the world and science await the next great invention that will revolutionize the world, will you be its inventor?

P.S. A notice before I say goodbye, if there is something that is not interpreted correctly, it is because I really speak only Spanish and I had to translate this instructable: 'v. If there is an error, please tell me in the comments. Thanks for your comprehension.

Participated in the
Invention Challenge 2017

Participated in the
Explore Science Contest 2017

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## 3 Discussions

I'm TOTALLY GEEKING OUT!!!

That's a neat model, it would be a cool educational tool :)