Words such as breadboard and prototype have an almost romantic allure in the electrical engineering world. Although the terms are sometimes used interchangeably, they are somewhat different: a breadboard usually is a basic, often somewhat crude rendition of a desired circuit, while a true prototype is closer to the final design and may also deal with packaging, appearance, manufacturing issues (assembly and tolerance), and even qualification tests.
Given the relentless move to higher frequencies – as the cliché says, “yesterday’s ceiling is tomorrow’s floor” – it may seem that there is little room for basic breadboards, since those frequencies are so sensitive to layout, parasitics, and other mysterious forces (even the ubiquitous FR-4 PC laminate is no longer adequate in many cases). But if you step back and look at what is in those designs, they usually also have a lot of lower-frequency analog and digital functions as well, with transducers for variables such as temperature, switch closures, pushbuttons, motors, and other tangible manifestations.
They may have processors, high pin counts, and under-package contacts, or GHz-band low-noise amplifiers with few pins and strict layout guidelines. Nonetheless, a closer look at their block diagram shows that there are still many ways in which the design is “modular” with lower-speed I/O, power subsystems, and many other functions outside of those highest-performance blocks. Given the realities of many designs, one obvious question is, “Can basic breadboards still function as prototypes?” The answer is yes in many cases, as long as the design can be functionally partitioned, which is often the situation.
Of course, we’re not talking here about the breadboard of the early days of electricity or electronics. In the early part of the 20th century, the makers of the period did use a literal breadboard – a wooden board used for cutting bread – as their experimental platform and even for the final circuit, by wrapping wires around nails (a pre-cursor of wire wrapping!) or soldering the wires to thumbtacks as connection points (Figure 1).
Figure 1 This battery-switch-resistor-LED breadboard does not use a classic incandescent bulb, but it is still a classic breadboard in the literals sense. Source: Instructables
You can find many pictures of these arrangements – as well as antique sort-of reproductions – ranging from basic AM crystal radios (Figure 2) to simple vacuum-tube AM radios using the triode valve invented by Lee de Forest in 1906. There was little need to worry about exposed wires with lethal voltages in those days, as most used a 6 or 12V “A battery” for the tube filament and a series of batteries delivering around 50V for the plate – below the level of danger. (Side note: that’s why there are no A or B batteries at your local store, while we have AA, AAA, C, and D; the A and B designations were already in use.)
Figure 2 This antique-looking crystal radio on a breadboard emulates the original models of the 1920s, but note the modern glass-enclosed diode in the lower right corner, rather than a galena mineral crystal and its finicky cat’s whisker contact. Source: Etsy
As experimental breadboarding became more popular, and there was a need for a way to easily attach and remove wires, connectors such as Fahnestock clips came into use (Figure 3). These were inexpensive, handy, easy to use, and – don’t be shocked – are still available, which is a testament to their utility.
Figure 3 These classical Fahnestock clips have been around for about 100 years and are still available for breadboarding. Source: Antique Electronic Supply
Obviously, when discrete transistors and even DIP ICs arrived, the wood-based breadboard was no longer viable, but the word remained in standard use. Among the popular options were “solderless” breadboards, which are still available in many configurations (Figure 4).
Figure 4 This basic solderless breadboard was very popular for use with DIP ICs and leaded components and is still widely used. Source: Adafruit via Digi-Key
If you do a web search, you’ll see there are many experimenters still using these for projects that use discrete leaded devices (transistors, LEDs, switches), sometimes with adapters for surface-mount ICs and passives (see a few examples here). Depending on the project and the designer, they can be neat and tidy (Figure 5) or evolve into somewhat of a messy arrangement (Figure 6).
Figure 5 The solderless breadboard and DIP/leaded components can be used to create a neat demonstration circuit. Source: Randunut
Figure 6 As circuit complexity increases, the solderless breadboard can easily start to become a “rat’s nest” of jumbled wires, this is an early-growth example. Source: Cornell University
However, these handy solderless breadboards are of limited use for both maker and even pre-commercial designs, which use Arduino or similar boards, Bluetooth or Wi-Fi connectivity, and more. Fortunately, there has been plenty of innovation to meet these breadboard and prototyping needs.
For example, I recently found out about a system called the Phase Dock Universal WorkBench, which can be used by individual experimenters and hobbyists (“makers”), in STEM-focused classrooms, and yes, even by professionals getting a start on what will become a commercial product (Figures 7 and 8).
Figure 7 A breadboard system such as this one from Phase Dock is much more aligned with today’s prototyping and experiment needs, and can even accommodate (but is not limited to) a solderless breadboard and handy screw terminals. Source: Phase Dock
Figure 8 The Phase Dock system can be used to handle mixed component-package projects, such as this testbed for a model railroad staging yard; the five green boxes receding into the background are motorized drives which control the setting of the track turnouts (also called switches). Source: Phase Dock
Not only does it support various modes of breadboarding including the solderless board, but it also provides a clean appearance which I can tell you from personal experience is important when presenting your ideas and project to a teacher, judges, and even to management or outside investors. It allows you to mount and protect pre-made modules (again, perhaps as an Arduino board) onto a base-plate matrix, then add additional areas for your own circuitry including sensors, relays, I/O, displays, LEDs, rotary encoders, and all sorts of peripheral hardware that is needed to really build, test, and explain the project.
The demise of most ICs in DIP housings and leaded components, along with wide use “canned” MCU pr RF modules, made it difficult at first for makers and others to continue to use the various solderless breadboards. Fortunately, innovation in electronics has spurred creative ideas for products, which enable serious and comprehensive breadboarding and prototyping by makers, experimenters, and engineers in a professional capacity, and do so without having to “etch” a PCB using an X-acto knife with a #11 blade (not fun at all, and you still have to drill those holes in bit-dulling FR4 — yikes!), a precise CAD-driven CNC router, or even one of those truly impressive LPKF machines.
What’s been your approach to breadboarding to test out an idea, topology, circuit approach, or their related algorithms? Do you kludge something together, or use a more formal method? Have you found a breadboarding and prototyping system that worked well for you with today’s processor-centric, RF-enabled designs?
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