Let’s take a look at the device and purpose of the breadboards. What is their advantage over other types of assembly, and how to work with them, as well as what schemes you can quickly build on them for a beginner?
The first problem that a radio amateur face is not even a lack of theoretical knowledge, but a lack of means and knowledge about how to assemble electronic devices. If you do not know how this or that part works, it will not prevent you from connecting it according to the electrical principle, but you need printed circuit board to clearly and efficiently assemble the circuit. Most often they are made according to the LUT method, but not everyone has a laser printer. Our fathers and grandfathers painted boards by hand with nail polish or paint, and then they were etched.
Here the newcomer is overtaken by the second problem – the lack of reagents for etching. Yes, of course, ferric chloride is sold in every store of radio-electronic components, but at first, and so you need to buy a lot and learn that it is simply difficult to pay attention to the technology of etching boards made of foil textolite. And not only for beginners but also experienced radio amateurs, it sometimes makes no sense to slack off a fee and spend money on an unfinished product at the stages of its adjustment.
To avoid problems with the search for ferric chloride, textolite, printer and not get from the wife (mother) for the unauthorized use of the iron, you can practice mounting electronic devices on solderless development boards.
What is a solderless breadboard?
As the name implies, this is such a board on which you can assemble the device layout without using a soldering iron. The mockup – as it is called by the people – is present in stores of different sizes and the models differ somewhat in layout, but the principle of operation and their internal structure are the same.
The prototype board consists of an ABS plastic case, in which are detachable connections that resemble dual metal tires between which the conductor is clamped. On the front of the case of the hole, numbered and marked, they can be inserted into wires, legs of the microcircuit, transistors and other radio components in the housings with leads. Take a look at the picture below, on it I have depicted all this.
On the considered printed circuit board, the extreme two columns of holes on each of the sides were joined vertically with common tires, of which the positive-contact power supply bus and the negative (common bus) are usually formed. Usually indicated by a red and blue stripe on the edge of the board plus and minus, respectively.
The middle part of the board is divided into two parts, each of the parts being joined along the line of five holes in a row on this particular board.
The internal structure of the board is shown in the figure below. Dual tires clamp the conductors as illustrated. Bold lines indicate internal connections.
Such boards in the English-language environment are called Breadboards by just such a name you can find it on aliexpress and similar online stores.
How to work with it?
Simply insert the legs of the electronic components into the holes, interconnecting the parts along horizontal lines, and feeding the extreme vertical ones. If you need a jumper, often use special ones with thin plugs on the end, in stores, you can find them under the name “jumper dupont” or jumpers for Arduino, by the way, you can also insert it into such a layout and assemble your projects.
If you didn’t have enough sizes of one development board, you can combine several, it is like puzzles inserted into each other, pay attention to the first picture in the article, the scheme is assembled on two connected boards. On one of them there is a spike, and on the other a notch, beveled from the outer part to the board body, so that the design does not collapse.
Build simple circuits on a breadboard
It is important for a beginner radio amateur to quickly assemble a circuit to make sure it works and understand how it works. Let’s take a look at how different layouts look on a breadboard.
The symmetric multivibrator circuit is recommended as the first for many beginners, it allows you to learn how to connect parts in series and in parallel, as well as to determine the pinout of transistors. It can be assembled by mounting or diluting a printed circuit board, but this requires soldering, and mounting, despite its simplicity, is in fact very difficult for beginners and is fraught with short circuits or poor contact.
See how simple it looks on a solderless breadboard.
By the way, note here that the Dupont jumpers were not used. In general, they can not always be found in radio stores, and especially in the shops of small towns. Instead, you can use the wires from the Internet cable (Twisted pair) they are isolated, and the core is not coated with varnish, which allows you to quickly expose the end of the cable by removing a small layer of insulation and insert it into the connector on the board.
You can connect the parts as you like, just to provide the desired chain, here is the same scheme, but assembled slightly differently.
By the way, to describe the connections, you can use the board marking, the columns are designated by letters, and the lines are numbers.
For your designs, there are such power supplies, they have plugs that are mounted in the solderless board by connecting to the tires “+” and “-“. It is convenient, it has a switch and a linear low-noise voltage regulator. In general, you will not be difficult to dilute such a fee yourself and collect it.
This is how you can connect an LED, for example, to test it. The picture shows a more “advanced” version of the PCB with clamping terminals for connecting the power supply. The anode of the LED is connected to the power supply (red bus) and the cathode to the horizontal bus of the working area, where it is connected to the current-limiting resistor.
The power supply on a linear stabilizer type L7805, or any other chip series L78xx, where xx – you need the voltage.
The assembled scheme tweeters on logic. The correct name of such a circuit is the Pulse Generator on the logical elements of type 2 and not. First, read the electrical schematic diagram.
As a logical chip suitable domestic K155LA3 or foreign type 74HC00. The elements R and C set the operating frequency. Here is its implementation on the board without soldering.
On the right is a white paper taped over a buzzer. It can be replaced by an LED if you reduce the frequency.
The greater the resistance or capacity, the lower the frequency.
But this is what a typical Arduinschik project looks like at the testing and development stage (and sometimes in the final form, depending on how lazy it is).
Actually, thanks to the Arduino project, the popularity of “brainboards” has recently increased significantly. They allow you to quickly assemble the circuit and check their performance, as well as use as a connector when flashing chips in a DIP package, and in other buildings, if there is an adapter.
Restricted Breadboard Restrictions
Despite its simplicity and obvious advantages over soldering, solderless layouts have several disadvantages. The fact is that not all circuits work normally in such a design, let’s take a closer look.
Overload and parasitic components
On solderless development boards, it is not recommended to assemble powerful converters, and especially pulse circuits. The first ones will not work normally due to the current capacity of the contact tracks. It is not necessary to climb for currents more than 1-2 Amperes, although there are also messages on the Internet that include 5 Amperes, draw your own conclusions and experiment.
Pulse circuits may not work at all due to a large number of parasitic capacitances and inductances in the circuit. The location of the tires is such that they run along with each other and have a fairly large area. This causes unnecessary pickups and does not improve the stability of the pulse and precision circuits.
Do not forget that high voltage is dangerous to life. Designing devices that work, for example, from 220 V is FORBIDDEN categorically. Although the findings are closed with a plastic panel, a bunch of conductors and jumpers can cause an accidental short circuit or electric shock!
A non-safety prototype board is suitable for simple circuits, analog circuits that do not make high demands on electrical connections and precision, automation and digital circuits that do not work at high speeds (GigaHerz and tens MegaHerz is too much). At the same time, high voltage and currents are dangerous, and for such purposes, it is better to use hinged mounting and printed circuit boards, while the beginner should not make hinged mounting of such circuits. The elements of solderless model boards are the simplest circuits of up to a dozen of elements and amateur projects on Arduino and other microcontrollers.