Monday, January 4, 2016

Electronics: Goals and Ideas

This year, we've added a physics-based elective strand, consisting of Experimental Design, Electronics, and Electrical Engineering.  The electronics course is a prerequisite for the EE course, but you don't have to take both. The experimental design course is a bit of a singleton, which I'll get to in another post, but I'm a month or so into the electronics course, and wanted to share some of the paradigms of the course and see if anyone had any helpful ideas or experience teaching HS electronics to add.
Big Ideas
  • The course is more of a phenomenological look at electronics than a physical ones. That is, we're dealing with it as electronics folks would, rather than as physicists would. We can't get into a lot of heavy Maxwell's equations action, and we're not getting into an extremely precise model of the physics of current flow (Matter and Interactions does a great job with this, but it's not within the goals of the course or the mathematical tools of the prerequisites), and no differential equations to deal with RC, RLC circuits, etc. I want students to have a practical understanding, supported by theory where necessary and possible.
  • There's a big emphasis on assembly, schematics, soldering, etc. I want students to be able to read and use a breadboard, a schematic, clip leads, meters, and to be able to solder.
  • I want to hit the most important devices and concepts - resistors, capacitors, various sensors, etc., and also classic combinations of components (which are applications of these), like voltage dividers, voltage regulators, rectifiers, etc. This is one spot where I'd love a lot of suggestions; my formal electronics training has principally been physical, rather than practical.
  • The primary lens through which I'm going to have the students comparing different classes of devices is the i-V curve. Batteries, resistors, diodes and LEDs, and PV cells are the primary devices that I have on that list. Let me know if there's something that I'm missing. Capacitors will be in there, too, but they don't fit well into this paradigm.
  • I'm using (supplemented by my own stuff) the Make:Electronics book. There's a great deal that I like about it and some things that I don't (particularly on the theoretical end), but it's a good place to start. Students also get the kit for the first set of experiments, too. That's pretty expensive, and I probably can buy the parts and distribute them to them next year for a much smaller cost to them.
The StandardsThese will likely wiggle a bit, but here's where I'm starting with the learning standards for the term. Seeing where we are now, I'm thinking that capacitors will wait until the next term (EE). Let me know if anything's missing, etc.! ...I'll likely split the power and energy stuff out as its own standard, either next year or before the end of this term.

Resistors

  • Apply the loop and junction rules to battery/resistor circuits, both qualitatively and quantitatively
  • Appropriately use Ohm’s law to describe one or more resistors
  • Analyze series and parallel circuits
  • Determine and apply equivalent resistance
  • Recognize, apply, and analyze iV curves of resistors and batteries
  • Determine the power expended by resistors and connect energy and time
  • Use current as a measurement of rate of charge flow

Switching

  • Identify and analyze open and short circuits
  • Use and analyze SPST, SPDT, and DPDT switches
  • Use and analyze relays
  • Analyze circuits containing PNP and NPN transistors

Capacitors

  • Understand relationship amongst voltage across a capacitor, charge stored in it, and its capacitance
  • Qualitatively analyze steady-state capacitor circuits
  • Apply the loop rule to circuits with capacitors
  • Determine and apply equivalent capacitance
  • Calculate energy stored in capacitors

PV Cells

  • Recognize and analyze iV curves of photovoltaic cells
  • Analyze PV cells in circuits

RC Circuits

  • Qualitatively analyze (graphs of) voltage, current, and charge as time goes on
  • Analyze the steady state of an RC circuit
  • Use the loop and junction rules to determine current, voltage, charge at some moment in time
  • Calculate and apply the time constant of simple RC circuits
  • Advanced: use equivalent circuits to determine time constant

Diodes

  • Differentiate between and apply ideal and realistic diode models
  • Compare diodes with resistors and batteries
  • Recognize and analyze a diode's iV curve
  • Understanding and apply the concepts of threshold and breakdown breakdown voltage

Project

Schematics

  • Recognize components on schematic:
  • Batteries
  • Switches
  • Capacitors
  • Resistors
  • Potentiometers
  • Diodes
  • LEDs
  • PV cells
  • Junctions
  • Draw schematic, given circuit (clip leads or breadboards)

Assembly

  • Construct circuit with clip leads, given schematic
  • Recognize components visually
  • Breadboard circuit, given schematic
  • Solder components, with or without perf board

Units

  • Properly and consistently use units
  • Fluently deal with metric prefixes
  • Convert units fluently
  • Check for proper unit cancelation

Algebra

  • When appropriate, use symbolic algebra (no numbers until the end)
  • Recognize unreasonable answers
  • Reason proportionally
  • Fluently solve equations

2 comments:

  1. Have you considered doing activities with 555 timers? They require some understanding of RC circuits, they give students practice in reading pin diagrams, and there are a lot of cool and fun applications.

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    Replies
    1. I hadn't; it's really interesting, though. Looks like a good review application of voltage dividers as well. Sounds good for the second term - thanks for the tip!

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