The breadboard is one of the most basic and simple components when you learn how to build a circuit. Because there are many small jacks on the board, all kinds of electronic components can be inserted or pulled out arbitrarily according to the need, which eliminates the welding process, saves the circuit assembly time, and the components can be reused, very suitable for the assembly, debugging and training of electronic circuits.

Picture of the exterior of the breadboard
Bread board
history

If you wanted to build a circuit before the 1960s, you might have used a technique called "wire-wrap," which involves connecting conductive columns around the wrapping wire to the same perfboard (protoboard). The circuitry was complicated, and although it is still used today, the breadboard made it easier to shape the circuit.
Wound circuit board

How it got its name

The name of the breadboard dates back to the days of vacuum tube circuits, when most of the circuit components were large enough to be connected by screws and nails attached to a cutting board. As the size of the circuit components grew smaller, the breadboard name stuck.

specifications

The size and specifications of the bread board are different, such as 170 holes (35*47mm), 400 holes (85*55mm), 800 holes (165*55mm), etc.

Breadboard dimensions
Breadboard dimensions
The four sides of each breadboard have bumps and grooves, which allow the breadboard of the same size to be stitched together, increasing the available space.

Bread board assembly
Bread board assembly
Some breadboards have glue on the back to make it easier to attach to different instruments.

Back of bread board
Back of bread board
Structure and internal structure

The whole plate is made of thermosetting phenolic resin, and there are metal strips at the bottom of the plate. Holes are drilled at corresponding positions on the plate so that the components can contact the metal strips when inserted into the holes, so as to achieve the purpose of conducting electricity. Generally, one metal strip is used to connect every five holes. There is usually a groove in the center of the board, which is designed for the need of integrated circuit, chip test. On either side of the board are two vertical rows of jacks (power rails), also in groups of five, to supply power to the components on the board.

Inside the breadboard metal connection
Inside the breadboard metal connection
1. Power rails

There are two rows of jacks on the upper and lower sides of the breadboard, which are generally used as power supply channels. The column marked "+" in the top row contains 5 sets of jacks, each set of 5 (5 internal holes are connected), all of which are positive terminals. The second column in the upper row marked with "-" has five sets of jacks, each set of five (five internal holes are connected), all of which are grounded. The first row under the breadboard is the same structure as the second row. If the whole breadboard is needed, wires are usually used to connect the "+" to the "+" and the "-" to the "-".

Breadboard power rail
Breadboard power rail
Breadboard power rail 2
Breadboard power rail 2
2. Connect rails

The connecting hole is divided into two parts, which is our main working area, used to plug in the original and jumper. The five jacks in the same column (a-b-c-d-e, f-g-h-i-j) are connected to each other; Columns (1-30) and the upper and lower parts of the grooves (e-f) are disconnected.

Breadboard wiring rail -1
Breadboard wiring rail -1
Breadboard wiring rail -2
Breadboard wiring rail -2
Step 3: Grooves

There is a long groove in the middle of the breadboard that acts as follows:

As shown in the figure below, the upper and lower parts of the breadboard are disconnected. ? The distance between the upper and lower grooves is 7.26mm, just enough to insert the standard narrow-body DIP pin integrated circuit (chip).

As there are many IC pins, it is not easy to take them off. It's easy to bend the pin or even break it if you pull it out violently, so this groove is just enough to reach under the IC with tweezers or something

Breadboard integrated circuit chips used
Breadboard integrated circuit chips used
How do you build a circuit on a breadboard

1. Series circuit

Breadboard series circuit
Breadboard series circuit
2. Parallel circuits

Breadboard parallel circuit
Breadboard parallel circuit
Use and precautions

1. When installing discrete components, it should be easy to see the polarity and mark. After straightening the pin of the component, bend it where needed. To prevent short-circuiting of exposed leads, a conductor with a sleeve must be used, and the element pins are generally not cut to facilitate reuse. Generally do not insert a component with a pin diameter greater than 0.8mm, so as not to damage the elasticity of the contact piece inside the socket.

2. Pins of integrated circuits that have been used for many times must be repaired neatly. Pins should not be bent and all pins should be slightly outward, so that the lead Angle can be reliably contacted with the jack. To determine the arrangement of components on the breadboard according to the circuit diagram, the purpose is to facilitate the wiring. To ensure proper wiring and easy cable checking, insert integrated circuits in the same direction. Do not insert an integrated circuit backwards to facilitate temporary wiring or shorten the length of the conductor.

3. According to the sequence of signal flow, the method of installation and debugging is adopted. After installing components, connect power cables and ground cables. In order to check the line convenience, the line as far as possible use different colors. For example, the positive power supply usually uses red wire. If the bread board uses negative power supply with blue wire, ground wire with black wire, signal line with yellow, can also choose other colors according to the conditions.

4. The bread board should use a single wire with a diameter of about 0.6mm. Cut the wire according to the distance of the wire and the length of the jack. Ask the wire head to be cut to 45? Diagonal, the peeling length of the thread is about 6mm, and it is required to be inserted into the bottom plate to ensure good contact. Bare wire should not be exposed outside to prevent disconnection with other wires.

5. The cable must be closely connected to the bread board to avoid collision and eject the bread board, resulting in poor contact. Must make the wire around the integrated circuit through, not allowed to straddle on the integrated circuit, may not make the wire overlap with each other, as far as possible horizontal and vertical, so as to check the line, replace the components and wire.

6. It is best to parallel a capacitor with a capacity of dozens of micromethods between the input end of each power supply and the ground, so as to reduce the influence of current in the transient process. In order to better suppress the high frequency component of the power supply, a high frequency decoupling capacitor should be connected in parallel at both ends of the capacitor. Generally, a single stone capacitor of 0.01 ~ 0.047μf should be used.

7. In the wiring process, each component is required to be placed in the corresponding position on the breadboard and the pin number used is marked on the circuit diagram to ensure the smooth debugging and fault finding.

8. All ground wires must be connected together to form a common reference point.

Principle of wiring

1. Minimize connections. Adding a connection point is equivalent to artificially increasing the probability of failure.

2. Try to avoid overpasses. The so-called "overpass" is a component or wire riding on other components or wires. Beginners are the most likely to make this mistake. Doing so, on the one hand, brings trouble to the replacement of components in the later period, on the other hand, when the fault occurs, the disorderly wire is easy to make people lose confidence.

3. Try to be solid. There are two phenomena that need to be noted: First, integrated circuits are easy to loosen, therefore, for the operation amplifier and other integrated circuits, it is necessary to press down, once not secure, need to change the position. Second, some components pin is too thin, should pay attention to gently toggle, if found to be unstable, need to change the position.

4. Convenient for testing. Do not fill up the five holes connected to the bread board. At least one hole should be set aside for testing.

5. The layout should be as compact as possible and the signal direction should be as reasonable as possible.

6. Try to approximate the schematic layout. This helps students find the location of components as soon as possible when looking for faults.

7. Use the power supply area as clearly as possible. Before the lap circuit, the power division is divided into positive power, ground and negative power three areas, and the connection is completed with wires.

To protect the

1, try to avoid water, debris and powder into the jack.

2, avoid rough plug of integrated circuit, so as not to fold the pin in the jack; Do not snap the wire in the jack.

3, do not insert too thick wire, probe, pin into the hole.

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