 The breadboards come in a number of sizes as single piece parts. Others are offered as units with multiple breadboards stacked next to each other and mounted on a panel, many with binding posts [banana jacks to accept power]. Complete units may be purchase were the breadboards are mounted to a housing which contains a power supply, switches, power jacks, displays and so on. The graphic shows a Solderless breadboard with Banana jack for power supply wiring. The main problem with the solid wire used is that the striped end tends to break after usage, sometimes the brake is clean and easily spotted while other times the wire may break after insertion into the board making it difficult to spot in the maze of other interconnecting wires. There are a large number of component or pin adapters available for purchase. These adapters allow a many styles of other components to be used with the breadboard that would not otherwise plug into the board's pin array [Dual In-Line or Single In-Line format]. Component Adapters include; Right angle surface mount PLCC adapters IDC Adapters [Shrouded Headers] Dual-Row adapters [Pin Headers] D-Sub Adapters Circular DIN or Mini-DIN Adapters Of course there's an added cost for these adapters, but they allow a denser circuit to be built on the breadboard with out the need to run long wires off-board to connect to a component sitting on a lab bench. Pre-designed circuits are available to plug into a breadboard. Circuit boards that have headers [male pins] are positioned so that they plug directly into a breadboard. For example a USB Power Supply, or Wall wart power supply can be purchased that plugs directly into the breadboard to provide power or a USB interface. This second picture shows breadboards stacked together allowing a much larger circuit to be constructed.  The most obvious problems with solderless bread-broads is that they only accept through-hole components. Of course the argument could be made that because the boards were only designed to accept through-hole components, that it's not a problem but a limitation. However adapters are available to convert some surface mount devices into through-hole components. The complexity of the circuits is limited, with the number of interconnecting wires becoming unwieldy and increasingly difficult to change or trouble-shoot. However just the size of a unit board should give an indication of a practical circuit, although the photo above shows four boards concatenated together. Even with color coded wires it would still be difficult to locate the destination of a wire that has come out of its plug. A large number of modern ICs are dense containing a large number of pins. Although some Dual In-Line ICs do extend up to as many as a 64-pin DIP, most revert to a surface mount package which would than require some SMD to through-hole converter board. This tends to relegate the solderless breadboard to Medium scale integrated circuits and glue logic ICs. Of course all the devices in a 4-sided PGA package would also require an adapter card. Modern ICs and many of the newer logic families switch levels in the nano-second range, regardless of the clock frequency used. Each of the unused pins in a connection row becomes an unterminated stub at that frequency. Running a large number of closely spaced ICs all switching at 1nS could cause noise in the circuit or false switching. Again this tends to limit the circuits that can be fabricated on this type of board, because it defeats the purpose of prototyping a board to test a new function if much of the debug time is spent just trying to get it to work on a surface that causes many new problems. Terminating the interconnects could alleviate some of the noise issues but that would double the number of I/O wires and increase the point-to-point wiring. Low noise analog devices poise another issue with each of these interconnect wires acting as a potential noise pick-up, or noise source. So in general these solderless breadboards do serve a function, but only with low density, out-dated ICs with slow switching speeds. Or low current general purpose analog devices with out noise issues. Adapters could be used to increase the usefulness of this type of prototyping, but at an increasing cost as the number or types of adapter boards are used. Because of these limitation, the designer has to have prior knowledge of the ICs that will make up the circuit design, and will have limited opportunities to change the circuit design based on the style of adapters available for purchase. DIPs are the least desirable IC package because of noise, size, ground bounce, lead inductance.... but this breadboard's clam to fame. One item I've never seen is the number of insertion cycles these plugs will take before failing. Many times connector data sheets will indicate the number of insertions a connector is designed for. A VME Connector for example, may be a class 1 to 3, with class three only designed to handle 300 mating cycles. |