20/12/11 Messy Test Bench
A messy desk is the sign of a genius?
Tidiness or the apparent lack of it was highlighted with the sad passing of Jim Williams and Bob Pease. Their work spaces had the outward appearance of chaos but no one is going to suggest that such approaches automatically lead to genius.
That said, what is it about test benches that generate interest and superficial anarchy? Perhaps part of the reason is that the tangible world is very different to the virtual virtues and disciplines instilled by working with computers. In the design environment there are many iterations and calculations. The myriad of details, trials and outcomes are all filed away - tidily. These processes lead to a final flurry of files which are sent by e-mail to the PCB manufacturer.
A crucial element of the electronic design process
It is only when that bare fibreglass with its intricate copper pathways is populated with the relevant components that it becomes an item of real world focus. The test bench is home to the transformation of all that theory and design into a working, functional device. It would be great to think that all the design work would lead to a device that works straight off. Sometimes that does happen and the test bench is tasked with a series of checks and measurements.
The most critical work on the test bench is encountered with high performance circuits pushing some kind of boundary. The device in the photo is the realisation of a circuit which is the subject of a patent application. There are several facets of the design that challenge the established approaches. This means that a great deal of work is empirical, backed and checked with calculation.
In the process various theories are tried in practice and monitored for their non-ideal behaviours. Some of these are predicted, others generate side effects that would be hard to simulate with any accuracy. The test bench currently has a variety of coils, ferrites and copper wire. All of these parts are combined in differing forms and styles. Each is moved from hand manufacture to the circuit. If the tests reject the part, then it is consigned to a proverbial corner of the bench. Apart from the cost, it is a brave person who would immediately resign them to the bin.
The same occurs with differing values of more regular components. Each step has a story and over the course of many designs, the accumulation of stories and their associated parts grows. The anarchy reigns in the physical presence of these residual “nearly made it” parts. Of course the excitement comes once the circuit works well.
From chaos comes order(s)
Many humble, lifeless circuit boards have transformed in to the precursors of the boards used in a variety of products. Some of these are in 10,000+ per annum products, others may only be in 10's but at very high value. The test bench was the foundation of all these practical circuits in their realisable form. The anarchy of the bench gives way to the ordered function of the electronics. The interest is generated from the comprehensive studies and testaments supporting the final outcome.
Posted by: Peter Hawkins on 20/12/11.