Week
5 - Filters
Here are my thoughts on the fifth week's material, etc.
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This week's material is
an introduction to electrical filters.
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First order filters only.
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Labs are designed to show
how filtering works to reduce noise in a signal.
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This year I found a good
filtering lab - after looking for years - and it was right under my nose.
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Later in the course I
use a liquid level system in the control segments. A pump pumps liquid
into a tube with an outflow orifice in the bottom of the tank. There's
a pressure sensor close to the base of the tube. There is a lot of
turbulence at the liquid surface and the pressure signal has a lot of noise
- and I should have noticed that before. I devised a lab
where students had to design a filter to reduce the turbulence noise in
the signal from the pressure sensor.
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In-Class exercises
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Class Notes - Good so
far, but I need a lot more.
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Some things to think about.
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In other years I used
a real fun lab - "Filter Appreciation
Day". Students got to "experience" filters using headphones,
etc. Would like to work this back in.
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Sensors encountered to
this point in the course.
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Thermocouples
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LM35s - giving two examples
of sensors with voltage outputs
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Thermistor - giving an
example of a sensor with a resistance change.
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AC Tachometer
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Pressure Sensor
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Thoughts about where this
is at this point.
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I think that filtering
the pressure sensor signal is better than Filter Appreciation Day for non-EEs.
but there were good aspects to things when students could listen to CDs
and filter the signals. They got a better feeling for what a filter
is???