Bench Talk

I spent most of Saturday at the Fort Worth Museum of Science and History for Engineer’s Week. I sat at a table with half a dozen kids at a time, showing them how to connect little DC motors to batteries, and exploring and explaining series and parallel connections for the braver ones. We had several DC motors with a glue stick off center on the shaft of the motor so it would wobble, and velcro attached the motor and battery holder with alligator clip leads to a scrub brush. The result was a giant hex bug popping around on the table. Some kids were very interested in how they could take it further, and others had glazed expressions. For the ones that wanted to go further, I showed them how to connect three 9V batteries in series to feed the motor 27 volts… and it really buzzed. Then I told them we were on the Mars Rover team and had to make sure that even if a lead broke, the rover would still go.

In this first post, I would like to talk a bit about the need for circuit protection in general. My view is that electronic devices should all have immunity to common surge events. That is to say, electronic devices should never fail due to ordinary and foreseeable electrical disturbances – be they ESD, induced lightning surges or incidental contact with AC power lines.