|
 | ||||||
 |
 |
 |
 |
 |
 |
||
| Company | |
|
Company Detail Enquiry Form Sitemap | |
| Design Services | |
|
Our Design method Spec'ing your job Hardware design Firmware design Examples: Circuits Examples: Photos | |
| |
Can't find it? Try:
| |
| Circuits | |
|
Serial to Parallel 89C2051 project Weighscale Light Key Index - Main Library | |
| Techniques Explained | |
|
Design step-by-step Circuit diagrams PCB Layout PCB Etching Prototyping Firmware design Documentation Manufacturing Economies of scale Test Procedures ECOs - changes | |
| Design Specification | |
|
Overview Specification Intro. Writing your Spec. Tech Ingredients Example Specs Designer selection R&D Economics Inspiration | |
| Pictures (=1000 words) | |
|
A PCB Factory Example projects ...more ...more A real design Lab | |
| Techniques in more detail | |
|
PCB EMI and ESD 2 wire I/O expansion | |
| Reference, etc | |
|
RS232 pinouts RS485 Autotrax P89LPC932 Past products | |
| Further info | |
|
Link library (15k+) Google search Google groups | |
FR-4 PCB Laminate
FR-4 PCB Laminate is the most commonly used base material for printed circuit boards. The "FR" means Flame Retardant (to UL94V-0), and Type "4" indicates woven glass reinforced epoxy resin.
You can see our demonstration of the FR-4 rating here - we have blowtorched the PCB on the right hand side of the image. While the PCB did flame slightly, the flames extinguished themselves. Only continued application of the blowtorch would reignite the laminate. The Glass weave itself becomes clearly visible in the carbonised burnt circuit board. The circuit board still has some mechanical strength - it is severely degraded, obviously, but it still supports the tracks and pads. At a low voltage, surprisingly, there is little conductance across the burnt area, it might still function in a marginal sense.
FR-4 is not Halogen free - that is, when igniting in an enclosed space it can potentially cause poisonous fumes. A number of companies are working on Halogen free versions of FR-4 laminate.
At the same time as we performed this test, we examined some common components - mainly to understand the concept applied to many plastics, that they may be allowed to burn, but they may not form flaming drips. One interesting anecdote: We thoroughly blowtorched a standard 0.25W 5% helical cut carbon film axial resistor; following the treatment its painted coating was just ash, the steel leads had lost their tinning, - but the resistance was still within tolerance.
Click the Continue arrow below for "Prototyping," or go on to:
- How to design a new electronic product
- Photographs of our work page 1, p2 p3 p4 p5
- Circuit Diagrams, examples of our work
- Our Design services, our Products, our contact Details
Seen on the door to a light-wave lab:
"Do not look into laser with remaining good eye."
PCB Layout