Breadboard

A plug-in board (English breadboard ), also called " breadboard " or "Proto Board", the mechanical mounting and electrical connection of electronic components used. Unlike PCBs, the components are not soldered on breadboards, but only plugged. This is particularly advantageous for experimental setups, since the circuit can be changed by simply changing. Plug-in boards are / training often used by hobbyists and sometimes in schools, since the structure quickly vonstattengeht and no soldering skills. An alternative to the breadboard make winding connection on breadboards dar.

Typical specifications

A plug-in board usually consists of a plastic plate in which a plurality of contact springs are ( nickel-plated [ Standard], tin or gold plated ). The distance between the contact springs is usually 0.1 inches (2.54 mm ), so that integrated circuits ( ICs) can be fitted with DIL package directly to the breadboard. The maximum current carrying capacity of the contact springs is typically 1 ampere, the permitted diameter of the components ports 0.3 to 0.8 mm ( AWG 20-28 ).

Connecting lines

The connection between the various electrical grids is made by the wired components themselves. Is that enough not because, for example, longer distances have to be bridged on the plug board connections can be made by means of lines. To interconnect to massive wires, flexible wires ( strands) are can not be inserted into the contacts. For commercial wires these connecting lines can be readily prepared themselves.

If, nevertheless, flexible cables must be used for the construction, it is recommended to solder an electrical contact pin on the line.

Are bare copper wires used without further surface treatment, there is a risk that it comes to corrosion over time ( the formation of copper oxide ). With increasing layer thickness of the electrical contact resistance between the contact terminal and the wire increases. In extreme cases this can lead to non-functioning of the circuit. In contrast, tin-plated copper wires are used, this effect does not occur.

Typically insulated cables are used. With bare wires there is a risk of short circuits in the circuit configuration when touching two wires.

Use of SMD components

For SMD components, there are commercially available special adapter boards. These boards have solder terminals for SMD components and additional solder cups with holes for through-hole components. In the holes then Headers example, can be soldered leaded version. The adapter board fully assembled can then be inserted into the contact springs on the breadboard.

Limitations

Due to parasitic capacitances and high, non-reproducible contact resistance at the contact springs of the area of ​​application of plug-in boards to smaller circuits with low frequencies (typically <10 MHz) limited. Circuits with a larger number of components are due to the high number of required jumpers quickly become confusing. On the breadboard just wired components and ICs can be used in DIL packages. The use of SMD components and ICs with other housing forms is possible only with elaborate adapters. In experimental setups with higher voltages is important to note that there is no voltage flashover between the different rows of contacts. The same applies to adjacent components and lines in the outdoor wiring. Similarly, the maximum current per contact point is limited. The heat dissipation is compared to structures with PCBs at breadboards very low, which can locally lead to a significant increase in component temperature.

Optical Breadboards

In the field of optics, the term refers to a breadboard metal plate with pre- threaded holes are set up and carried out on the optical experiments. Breadboards are usually made ​​of aluminum, partly from other materials, such as steel. For high-precision set-ups an external vibration damping is often still necessary. For very large structures large optical tables are used instead of breadboard, we have also integrated a vibration damping in the normal case.