How to use a breadboard for solderless mounting. Bread board

Breadboard design for modeling electronic circuits. (10+)

DIY breadboard

When developing various electronic devices, I often encounter the need to make a layout. Of course mathematical modeling is a great thing. But First of all, not all schemes lend themselves to mathematical modeling, but Secondly, the mathematical model is not accurate enough. In general, after checking on a computer, it is imperative to assemble it live. At first I made a test circuit board, realizing that then it would have to be thrown away. But then I started using a breadboard. I don't like breadboards based on foil textolite at all. The reason is that they do not tolerate frequent soldering. From periodic heating, the conductors begin to lag behind. So a printed breadboard is almost as disposable as a test board designed for a specific device.

Homemade breadboard drawing

In the end, I made a breadboard using my own technology, which I really liked. Now I use it everywhere. The board was made from non-foil textolite. You can take foil and remove the foil.

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Printed circuit board- this is a dielectric base, on the surface and in the volume of which conductive paths are applied in accordance with the electrical circuit. The printed circuit board is designed for mechanical fastening and electrical connection between each other by soldering the leads of electronic and electrical products installed on it.

The operations of cutting a workpiece from fiberglass, drilling holes and etching a printed circuit board to obtain current-carrying tracks, regardless of the method of drawing a pattern on a printed circuit board, are performed using the same technology.

Manual application technology
PCB tracks

Template preparation

The paper on which the PCB layout is drawn is usually thin and for more accurate drilling of holes, especially when using a handmade home-made drill, so that the drill does not lead to the side, it is required to make it denser. To do this, you need to glue the printed circuit board pattern on thicker paper or thin paper. thick cardboard using any glue, such as PVA or Moment.

Cutting a workpiece

A blank of foil fiberglass is selected right size, the printed circuit board template is applied to the workpiece and outlined around the perimeter with a marker, a soft pencil or drawing a line with a sharp object.

Next, fiberglass is cut along the marked lines using metal scissors or cut with a hacksaw. Scissors cut faster and no dust. But it must be taken into account that when cutting with scissors, fiberglass is strongly bent, which somewhat worsens the strength of gluing copper foil, and if re-soldering of the elements is required, the tracks may peel off. Therefore, if the board is large and with very thin tracks, then it is better to cut it off with a hacksaw.

A printed circuit board pattern template is glued onto the cut-out blank using Moment glue, four drops of which are applied to the corners of the blank.

Since the glue sets in just a few minutes, you can immediately start drilling holes for radio components.

Hole drilling

It is best to drill holes using a special mini drilling machine with a 0.7-0.8 mm carbide drill. If mini drilling machine not available, you can drill holes with a low-power drill with a simple drill. But when working with a universal hand drill the number of broken drills will depend on the hardness of your hand. One drill is definitely not enough.

If the drill cannot be clamped, then its shank can be wrapped with several layers of paper or one layer of sandpaper. It is possible to wind tightly coil to coil of a thin metal wire on the shank.

After drilling is completed, it is checked whether all holes have been drilled. This is clearly visible if you look at the printed circuit board through the light. As you can see, there are no missing holes.

Drawing a topographic drawing

In order to protect the places of the foil on the fiberglass that will be conductive paths from destruction during etching, they must be covered with a mask that is resistant to dissolution in an aqueous solution. For the convenience of drawing tracks, it is better to pre-mark them with a soft, simple pencil or marker.

Before marking, it is necessary to remove traces of Moment glue, which glued the printed circuit board template. Since the glue has not hardened much, it can be easily removed by rolling it with your finger. The surface of the foil must also be degreased with a rag by any means, for example, acetone or white alcohol (the so-called refined gasoline), you can use any detergent for washing dishes, such as Ferry.

After marking the tracks of the printed circuit board, you can begin to apply their pattern. Any waterproof enamel is well suited for drawing tracks, for example alkyd enamel PF series, diluted to a suitable consistency with white spirit solvent. You can draw tracks different tools- a glass or metal drawing pen, a medical needle and even a toothpick. In this article, I will show you how to draw PCB tracks using a drawing pen and a ballerina, which are designed to be drawn on paper with ink.

Previously, there were no computers and all the drawings were drawn with simple pencils on whatman paper and then transferred with ink to tracing paper, from which copies were made using copiers.

Drawing a picture begins with contact pads, which are drawn with a ballerina. To do this, you need to adjust the gap of the sliding jaws of the drawer of the ballerina to the required line width and to set the diameter of the circle, adjust the second screw by moving the drawer from the axis of rotation.

Next, the drawer of the ballerina for a length of 5-10 mm is filled with paint with a brush. For applying a protective layer on a printed circuit board, paint of the PF or GF brand is best suited, as it dries slowly and allows you to work calmly. NC brand paint can also be used, but it is difficult to work with it, as it dries quickly. The paint should lay down well and not spread. Before drawing, the paint must be diluted to a liquid consistency, adding a suitable solvent to it little by little with vigorous stirring and trying to draw on scraps of fiberglass. To work with paint, it is most convenient to pour it into a nail polish bottle, in the twist of which a solvent-resistant brush is installed.

After adjusting the drawer of the ballerina and obtaining the required line parameters, you can begin to apply contact pads. To do this, the sharp part of the axis is inserted into the hole and the base of the ballerina is rotated in a circle.

At correct setting drawing pen and the desired consistency of paint around the holes on printed circuit board perfect circles. round shape. When the ballerina begins to draw poorly, the remnants of dried paint are removed from the drawer gap with a cloth and the drawer is filled with fresh paint. to outline all the holes on this printed circuit board with circles, it took only two refills of the drawing pen and no more than two minutes of time.

When the round contact pads on the board are drawn, you can start drawing conductive tracks using a manual drawing pen. The preparation and adjustment of a manual drawing pen is no different from the preparation of a ballerina.

The only thing that is additionally needed is a flat ruler, with pieces of rubber glued on one of its sides along the edges, 2.5-3 mm thick, so that the ruler does not slip during operation and the fiberglass, without touching the ruler, can freely pass under it. A wooden triangle is best suited as a ruler, it is stable and at the same time can serve as a support for the hand when drawing a printed circuit board.

So that the printed circuit board does not slip when drawing tracks, it is advisable to place it on a sheet of sandpaper, which is two sandpaper sheets riveted together with paper sides.

If, when drawing paths and circles, they touched, then no action should be taken. It is necessary to allow the paint on the printed circuit board to dry to a state where it will not stain when touched and remove with a knife edge extra part drawing. In order for the paint to dry faster, the board must be placed in a warm place, for example, in winter time to the heating battery. In the summer season - under the rays of the sun.

When the pattern on the printed circuit board is completely applied and all defects are corrected, you can proceed to etching it.

Printed circuit board drawing technology
using a laser printer

When printing on a laser printer, the image formed by the toner is transferred due to electrostatics from the photo of the drum, on which laser ray drew an image on paper. The toner is held onto the paper, preserving the image, only due to electrostatics. To fix the toner, the paper is rolled between rollers, one of which is a thermal oven heated to a temperature of 180-220°C. The toner melts and penetrates the texture of the paper. After cooling, the toner hardens and adheres firmly to the paper. If the paper is heated again to 180-220°C, the toner will again become liquid. This property of the toner is used to transfer the image of current-carrying tracks to a printed circuit board at home.

After the file with the printed circuit board drawing is ready, you need to print it using laser printer on paper. Please note that the image of the printed circuit board drawing for this technology must be viewed from the side of the installation of parts! Jet printer is not suitable for these purposes, as it works on a different principle.

Preparing a paper template for transferring a pattern to a printed circuit board

If you print a printed circuit board pattern on ordinary paper for office equipment, then due to its porous structure, the toner will penetrate deeply into the body of the paper and when the toner is transferred to the printed circuit board, most of it will remain in the paper. In addition, there will be difficulties with removing paper from the printed circuit board. You will have to soak it in water for a long time. Therefore, to prepare a photomask, you need paper that does not have a porous structure, such as photographic paper, a substrate from self-adhesive films and labels, tracing paper, pages from glossy magazines.

As the paper for printing the PCB design, I use tracing paper from old stock. Tracing paper is very thin and it is impossible to print a template directly on it, it jams in the printer. To solve this problem, before printing on a piece of tracing paper of the required size, apply a drop of any glue in the corners and stick it on a sheet of A4 office paper.

This technique allows you to print a printed circuit board pattern even on the thinnest paper or film. In order for the toner thickness of the pattern to be maximum, before printing, you need to configure the “Printer Properties” by turning off the economical printing mode, and if this function is not available, then select the roughest type of paper, such as cardboard or something like that. It is quite possible that a good print will not work the first time, and you will have to experiment a little by choosing best mode laser printer printing. In the resulting print of the pattern, the tracks and contact pads of the printed circuit board must be dense without gaps and smearing, since retouching on this technological stage useless.

It remains to cut the tracing paper along the contour and the template for the manufacture of the printed circuit board will be ready and you can proceed to the next step, transferring the image to the fiberglass.

Transferring a pattern from paper to fiberglass

Transferring the PCB pattern is the most critical step. The essence of the technology is simple, paper, with the side of the printed pattern of the tracks of the printed circuit board, is applied to the copper foil of the fiberglass and pressed with great effort. Next, this sandwich is heated to a temperature of 180-220°C and then cooled to room temperature. The paper is torn off, and the pattern remains on the printed circuit board.

Some craftsmen suggest transferring a pattern from paper to a printed circuit board using an electric iron. I tried this method, but the result was unstable. It is difficult to simultaneously heat the toner to the desired temperature and evenly press the paper against the entire surface of the printed circuit board when the toner solidifies. As a result, the pattern is not completely transferred and there are gaps in the pattern of PCB tracks. It is possible that the iron did not heat up enough, although the regulator was set to the maximum heating of the iron. I did not want to open the iron and reconfigure the thermostat. Therefore, I used another technology that is less laborious and provides a hundred percent result.

On a printed circuit board cut to size and degreased with acetone, a blank of foil fiberglass was glued to the corners of a tracing paper with a pattern printed on it. On top of the tracing paper put, for a more uniform pressure, heels of sheets of office paper. The resulting package was placed on a sheet of plywood and covered with a sheet of the same size on top. This whole sandwich was clamped with maximum force in the clamps.

It remains to heat the made sandwich to a temperature of 200 ° C and cool. An electric oven with a temperature controller is ideal for heating. It is enough to place the created structure in a cabinet, wait for the set temperature to reach, and after half an hour remove the board for cooling.

If there is no electric oven available, then you can use gas oven by adjusting the temperature with the gas supply knob according to the built-in thermometer. If there is no thermometer or it is faulty, then women can help, the position of the regulator knob, at which pies are baked, will do.

Since the ends of the plywood were warped, just in case, I clamped them with additional clamps. to avoid this phenomenon, it is better to clamp the printed circuit board between metal sheets 5-6 mm thick. You can drill holes in their corners and clamp the printed circuit boards, tighten the plates with screws and nuts. M10 will be enough.

After half an hour, the design has cooled down enough for the toner to harden, the board can be removed. At the first glance at the removed printed circuit board, it becomes clear that the toner transferred from the tracing paper to the board perfectly. The tracing paper fit snugly and evenly along the lines of the printed tracks, the rings of the pads and the marking letters.

The tracing paper easily came off almost all tracks of the printed circuit board, the remains of the tracing paper were removed with a damp cloth. But still, there were gaps in several places on the printed tracks. This can happen as a result of uneven printing of the printer or remaining dirt or corrosion on the fiberglass foil. Gaps can be filled with any waterproof paint, nail polish or retouched with a marker.

To check the suitability of a marker for retouching a printed circuit board, you need to draw lines on paper with it and moisten the paper with water. If the lines do not blur, then the retouching marker is suitable.

Etching a printed circuit board at home is best in a solution of ferric chloride or hydrogen peroxide with citric acid. After etching, the toner from the printed tracks is easily removed with a swab dipped in acetone.

Then holes are drilled, conductive paths and contact pads are tinned, and radioelements are soldered.

This form was taken by a printed circuit board with radio components installed on it. The result was a power supply and switching unit for electronic system, supplementing an ordinary toilet bowl with a bidet function.

PCB etching

To remove copper foil from unprotected areas of foil fiberglass in the manufacture of printed circuit boards at home, radio amateurs usually use chemical method. The printed circuit board is placed in an etching solution and due to chemical reaction copper, unprotected by the mask, dissolves.

Etching solution recipes

Depending on the availability of components, radio amateurs use one of the solutions shown in the table below. Etching solutions are listed in order of popularity for their use by radio amateurs in the home.

Etch printed circuit boards in metal utensils are not allowed. To do this, use a container made of glass, ceramic or plastic. It is allowed to dispose of the spent pickling solution into the sewer.

Etching solution of hydrogen peroxide and citric acid

A solution based on hydrogen peroxide with citric acid dissolved in it is the safest, most affordable and fastest working. Of all the listed solutions, by all criteria, this is the best.

Hydrogen peroxide can be purchased at any pharmacy. Sold in the form of a liquid 3% solution or tablets called hydroperite. To obtain a liquid 3% solution of hydrogen peroxide from hydroperite, you need to dissolve 6 tablets weighing 1.5 grams in 100 ml of water.

Citric acid in the form of crystals is sold in any grocery store packaged in bags weighing 30 or 50 grams. Table salt can be found in any home. 100 ml of pickling solution is enough to remove 35 µm thick copper foil from a 100 cm2 printed circuit board. The spent solution is not stored and cannot be reused. By the way, citric acid can be replaced with acetic acid, but because of its pungent smell, you will have to pickle the printed circuit board in the open air.

Pickling solution based on ferric chloride

The second most popular pickling solution is an aqueous solution of ferric chloride. Previously, it was the most popular, since on any industrial enterprise ferric chloride was easy to get.

The etching solution is not picky about the temperature, it etchs rather quickly, but the etching rate decreases as the ferric chloride in the solution is consumed.

Ferric chloride is very hygroscopic and therefore quickly absorbs water from the air. As a result, a yellow liquid appears at the bottom of the jar. This does not affect the quality of the component and such ferric chloride is suitable for the preparation of an etching solution.

If the used solution of ferric chloride is stored in an airtight container, then it can be used repeatedly. To be regenerated, it is enough to pour iron nails into the solution (they will immediately be covered with a loose layer of copper). Leaves hard-to-remove yellow spots. At present, a solution of ferric chloride for the manufacture of printed circuit boards is used less frequently due to its high cost.

Etching solution based on hydrogen peroxide and hydrochloric acid

Excellent pickling solution, provides high pickling speed. Hydrochloric acid, with vigorous stirring, is poured into a 3% aqueous solution of hydrogen peroxide in a thin stream. Pouring hydrogen peroxide into acid is unacceptable! But due to the presence of hydrochloric acid in the etching solution, great care must be taken when etching the board, since the solution corrodes the skin of the hands and spoils everything it gets on. For this reason, an etching solution with hydrochloric acid at home is not recommended.

Etching solution based on copper sulphate

The method of manufacturing printed circuit boards using copper sulphate is usually used if it is impossible to manufacture etching solutions based on other components due to their unavailability. Copper sulfate is a pesticide and is widely used for pest control in agriculture. In addition, the PCB etching time is up to 4 hours, while it is necessary to maintain the temperature of the solution at 50-80°C and ensure that the solution is constantly changed at the etched surface.

PCB etching technology

To etch the board in any of the above etching solutions, glass, ceramic or plastic tableware, for example from dairy foods. If there is no suitable container size at hand, then you can take any box of thick paper or cardboard of a suitable size and line its inside plastic wrap. An etching solution is poured into the container and a printed circuit board is carefully placed on its surface with a pattern down. Due to the forces of the surface tension of the liquid and the low weight, the board will float.

For convenience, you can glue a cork from plastic bottle. The cork will simultaneously serve as a handle and a float. But there is a danger that air bubbles form on the board and in these places the copper will not corrode.

To ensure uniform etching of copper, you can put the printed circuit board on the bottom of the tank with the pattern up and periodically shake the bath with your hand. After a while, depending on the pickling solution, areas without copper will begin to appear, and then the copper will completely dissolve on the entire surface of the printed circuit board.

After the final dissolution of copper in the pickling solution, the printed circuit board is removed from the bath and thoroughly washed under running water. running water. The toner is removed from the tracks with a rag soaked in acetone, and the paint is well removed with a rag soaked in a solvent that was added to the paint to obtain the desired consistency.

Preparing the printed circuit board for the installation of radio components

The next step is to prepare the printed circuit board for the installation of radio elements. After removing the paint from the board, the tracks must be processed in a circular motion with a small sandpaper. You don’t need to get carried away, because the copper tracks are thin and can be easily grinded off. Just a few passes with a low-pressure abrasive is sufficient.

Further, the current-carrying tracks and contact pads of the printed circuit board are covered with alcohol-rosin flux and tinned soft solder eclectic soldering iron. so that the holes on the printed circuit board are not tightened with solder, you need to take a little of it on the soldering iron tip.

After completing the manufacture of the printed circuit board, all that remains is to insert the radio components into the intended positions and solder their leads to the sites. Before soldering, the legs of the parts must be moistened alcohol-rosin flux. If the legs of the radio components are long, then they must be cut with side cutters before soldering to a protrusion length of 1-1.5 mm above the surface of the printed circuit board. After completing the installation of the parts, it is necessary to remove the remains of rosin using any solvent - alcohol, white spirit or acetone. They all successfully dissolve rosin.

This simple capacitive relay circuit took no more than five hours to complete from the PCB traces to a working prototype, much less than the layout of this page.

The prototyping board is a universal, that is, a surface specially designed for mounting a variety of radio components. It has hundreds of holes, which are electrically connected with metal strips. The conclusions of microcircuits and radio components are inserted into these small holes, and then connected by means of pieces of stripped wires. At the same time, the rows of contacts located at the top, bottom and in the middle of the board are designed to connect the numerous points of the circuit with ground and a power source. It should be especially noted that the breadboard does not require a soldering iron, flux and solder. In addition, when working with it, there is no risk of overheating of the part, and there are no difficulties with repeated installation of circuits.

Types of breadboards

Currently, experts distinguish three main types of prototyping boards. Firstly, these are universal models, on the surface of which there are only

plated holes. Subsequently, the developer will have to connect them using jumpers. The second type is specialized boards. On such surfaces there are both standard chains (pre-wired) and tracks and holes designed for non-standard chains. And finally, the third type is the printed breadboard, designed for digital devices. In this case, power rails are drawn over the entire surface, and the intended places for microcircuits are also outlined.

Breadboard made by hand

Making a homemade board, if necessary, is quite simple and within the power of any person. As a material for its base, non-foil textolite is best suited. In this case, the lines of the breadboard can be applied using a ruler and a sharp awl. As for the holes, they can be made using a 0.8 drill. The conductors themselves can be made from and the necessary radio components are installed by soldering. In this case, all elements are not attached from the bottom side, but from the top. In addition, it is very important that the conclusions

The radio components were bent in such a way that they ran parallel to the contact conductors. The basis of the breadboard is ready!

Problems in the use of prototyping boards

Developers who, by virtue of their activities, constantly use prototypes of various electronic devices, note that their use is usually associated with a number of problems. The first of these is the most obvious and lies in the fact that any prototyping board is soldered by hand. And if an error is made in the circuit, it has to be re-soldered. Secondly, it should be said that in order to create a single prototype of an electronic device, it is quite often simply unprofitable to make a printed circuit board. Thirdly, if circuits on analog microcircuits of a low degree of integration are allowed to be carried out by a hinged mounting method, then microprocessor equipment is very difficult to do so. With all of these aspects in mind, it is essential to analyze everything in advance before starting to work with a device such as a prototyping board.

Lately I've been searching optimal design circuit board. Something like striving for excellence. The circuit board is generally a convenient thing, you look at circuit diagram and collect on it the same configuration. The electronic components soldered into a single whole follow the outline of the circuit diagram. It helps a lot when work on the unfinished was postponed for some time (sometimes a lot). When returning to the project, it is enough to put the diagram and the installation in front of you, and you don’t need to remember anything - everything is visible and understandable. The last "worked" installations with transformers installed on them. And if on one it is intended for a specific device (after debugging it will be removed and installed in its case), then on the other (smaller size) it is stationary.

I didn’t select anything on purpose, one of the power supply boards from the Rubin TV caught my eye - so I took it up.

I removed everything superfluous, leaving only a switch, a transformer and what was available from the connectors, and fuse holders.

With reverse side The board had a number of very powerful tracks, which, of course, can come in handy in the future. However, a significant part of them (marked with a red felt-tip pen), if their connection was not changed, would be a voltage conductor of 220 volts, which is unacceptable for the operation of an open-type circuit board.

As a result, the following changes were made - the printed conductors are not connected to the switch contacts, and the mains power cable is soldered directly to these contacts.

For comfort further work over the future circuit board and its use, attached improvised legs to it, put a key on the switch. The fuse holders had to be removed (the tracks were cut).

The step-down transformer on the board will be connected to the network through a wire that has a fuse block with a rating of 0.5 A each in the gap. External contacts of the switch under voltage 220 V were closed from accidental contact with plastic pads (glued with glue).

The switch contacts on the reverse side were also insulated. The mains cable is securely attached to the edge of the circuit board.

The official technical data of the transformer TP-8-3, standing on the circuit board, are as follows:

In fact, the maximum AC output voltage was 16.4 V. And the rectified maximum voltage is 14.4 V.

A different combination of connecting the ends of the secondary winding, which has a tap, gives an output of another 8.6 V and 5.4 V. The available voltage and current will be suitable for powering most different simple schemes. The diode bridge does not have a permanent connection to the transformer and can easily be excluded from the circuit if AC voltage is needed for power supply.

Finished circuit board. It already has a sufficient number of holes for installing pin contacts, to which electronic components will be soldered. Contacts (pins) do not have their own permanent place, but are installed in the place of the circuit board, where it is necessary for the specifically assembled circuit.

The circuit board is an auxiliary device, it is not an end, but a means to an end. And I would venture to express the idea that it would be right not to do such things “from scratch”, it is better to adapt something suitable. And then "hands may never reach the main thing."

Often, in order to quickly assemble a layout of some kind electronic circuit on the table, it is convenient to use the prototyping board, which eliminates the need for soldering. And only then, when you are convinced that your circuit is working, you can take care of creating a printed circuit board with soldering. For a person who is just starting to learn the world of electronics, it may not be obvious to use such a tool as a breadboard or “bredboard” (breadboard). Let's see what a breadboard is and how to work with it.

Instructions for working with a solderless breadboard (bradboard)

We will need:

• Breadboard (breadboard), buy;
• connecting wires (I recommend this set);
• LED (can be bought);
• 330 ohm resistor or close to it (an excellent set of resistors of all popular ratings);
• battery type "Krona" at 9 volts.

1 Description breadboard

There are many types of breadboards. They differ in the number of pins, the number of buses, and the configuration. But they are all built on the same principle. The breadboard consists of a plastic base with many holes, usually spaced at standard 2.54mm pitch. With the same step, the legs are usually located at the output microcircuits. Holes are needed in order to insert radioelement leads or connecting wires into them. typical view breadboard is shown in the figure.

Different types of breadboards (breadboard)

Own English title- breadboard (“board for bread”) - this type of board was obtained due to comparison with a board for cutting bread: it is suitable for quick “cooking” of simple circuits.

There are also solderable breadboards. They differ in that they are usually made of fiberglass, and their metallized pads are well suited for soldering wires and output radio elements to them. In this article, we do not consider such boards.

2 Device breadboard

Let's see what's inside the breadboard. The figure on the left shows general form fees. On the right side of the figure, the busbars are color-coded. Blue color- this is the “minus” of the circuit, red is the “plus”, green are the conductors that you can use at your discretion to connect the parts electrical circuit assembled on a breadboard. Note that the center holes are connected in parallel rows across the breadboard, not lengthwise. Unlike power rails, which are placed along the edge of the breadboard along its edges. As you can see, there are two pairs of power rails, which allows you to supply two different voltages to the board if necessary, for example, 5 V and 3.3 V.

The two groups of cross conductors are separated by a wide groove. Thanks to this recess, microcircuits in DIP packages (cases with "legs") can be placed on a prototyping board. Like the picture below:

There are also radio elements for surface mounting (their "legs" during installation are not inserted into the holes in the printed circuit board, but are soldered directly to its surface). They can be used with a similar breadboard only with special adapters - clamping or soldering. Universal adapters are called "zero gain panels" or ZIF panels, using foreign terminology. Such adapters are most often for 8-pin microcircuits and for 16-pin microcircuits. An example of such elements and such an adapter is shown in the illustration.

The numbers and letters on the breadboard are needed so that you can more easily navigate the board, and, if necessary, draw and sign your circuit diagram. This can sometimes come in handy during installation. big schemes, especially if you mount by description. Use them in much the same way as letters and numbers on a chessboard, for example: connect the resistor output to the E-11 socket, etc.

3 Assembling the scheme on the breadboard

To acquire the skill of working with a prototyping board, we will assemble the simplest circuit, as it shown on the picture. We connect the "plus" of the batteries to the positive bus of the breadboard, the "minus" - to the negative bus. The bright red and black lines are the connecting wires, and the pale translucent lines are the connections that the breadboard provides, they are shown for clarity.