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Posted by D Sherman [72.47.9.228] on Monday, June 20, 2011 at 18:50:11 :
In Reply to: Re: Auto electrics ? experts please posted by TGP (IL) [64.12.116.76] on Monday, June 20, 2011 at 18:33:32 :
No "resistor" is going to help if the problem is a weak design that's too fragile when faced with voltage fluctuations and spikes. A "load dump" transient in an automotive system, such as when you momentarily disconnect the battery while the engine is running, can reach 100 volts. As I mentioned, 30 volt spikes are common. There are good design practices that don't cost much that allow an electronic device to survive that kind of environment, but sometimes the bean-counters don't want to spend an extra penny, and more often the engineers who design this stuff simply aren't very good. I've seen designs where they could have made it simpler, cheaper, AND more reliable, but they didn't because the engineer just wasn't all that bright and there was apparently no design review process where the more senior guys could look at the design and say, "Why did you do it that way?" Unfortunately "made in USA" is no guarantee that the engineering was done right. I've worked with guys (in America) who thought that if the simulator told them it was good, then it was good, or if they built one in the lab and got it to work, then they'd all work in the factory. A lot of engineers don't have real-world experience these days and they don't know that they have to make their designs survive real-world conditions.