Byte and Switch (Part 2)
In part 1 we talked about the use of a MOSFET for a power switch. Here's a different circuit that also uses a MOSFET, this time as a switch for signals:
We have a thermistor Rth that is located somewhere in an assembly, that connects to a circuit board. This acts as a variable resistor that changes with temperature. If we use it in a voltage divider, the midpoint of the voltage divider has a voltage that depends on temperature. Resistors R3 and R4 form our reference resistance; when...
Byte and Switch (Part 1)
Imagine for a minute you have an electromagnet, and a microcontroller, and you want to use the microcontroller to turn the electromagnet on and off. Sounds pretty typical, right?We ask this question on our interviews of entry-level electrical engineers: what do you put between the microcontroller and the electromagnet?We used to think this kind of question was too easy, but there are a surprising number of subtleties here (and maybe a surprising number of job candidates that were missing...
Organizational Reliability
I was cleaning out my email inbox at work today and ran across something I had forwarded on to a friend a few years ago, which I thought I would share, for those of you who are working in the engineering world.
Below is a handout I got about 10 years ago from Doug Field, an executive now at Apple. Doug is a superb and inspiring leader, whom I had the opportunity to work with briefly.
The following is a bit of a diversion from the topics I usually post, but is some good food for thought for...
Oh Robot My Robot
Oh Robot! My Robot! You’ve broken off your nose! Your head is spinning round and round, your eye no longer glows, Each program after program tapped your golden memory, You used to have 12K, now there is none that I can see, Under smoldering antennae, Over long forgotten feet, My sister used your last part: The chip she tried to eat.
Oh Robot, My Robot, the remote controls—they call, The call—for...
Scorchers, Part 4: Burned by the Happy Path (Simon Says)
As engineers, we have to think carefully about how our designs may be used in ways we did not foresee. You may have heard of the happy path, which describes a sequence of events someone takes to use a product — whether it’s software or hardware. The line between software and hardware has gotten pretty blurry in recent years due to the prevalence of embedded systems. (Good news for embedded engineers!) Things have gotten
Sheep Bridge: In Praise of Generalists and System Engineers
Today I want to talk about generalists and system engineers: why they’re important and why they’re different from each other.
Specialists and GeneralistsA specialist is someone who has a very deep understanding of a particular subject, and spends much of the time working on aspects of that subject. Few others are capable of doing the specialist’s work. I recently wrote an article on gate drive design (Lost Secrets of the H-Bridge,...
