New 'Big Project' activity board a
treasure-trove of teaching possibilities
The ARRL Education and Technology Program (ETP - also known as "The
Big Project") will offer a new activity board to schools this fall.
ETP Coordinator Mark Spencer, WA8SME, says the "L/C/Resonance"
or L/C/R activity board will allow students to explore many facets of
alternating current and RF theory. The board will help students to unravel
the mysteries of capacitive and inductive reactance, verify reactance
formulas using actual data taken from the activity board, measure the
resonant frequency of either series or parallel L/C circuits and then
put it all together to explore the relationship between capacitive and
inductive reactance and resonance. And there's more, Spencer points out.
"Because the board uses a microcontroller and a digital-to-analog
converter (DAC) to generate the ac waveform used to explore L/C circuits,
there is an additional learning opportunity: digital signal processing
(DSP) fundamentals," he notes. "This facet of the board leads
to exploration of root mean square (rms) voltage and current and the
mathematical derivation of rms."
Given the level of mathematics involved, Spencer says the activity board
is intended primarily for high school physics or second-year algebra students.
But, he adds, anyone studying for the General or Amateur Extra license
examination could benefit from the learning opportunities the L/C/R activity
board affords.
"In other words," Spencer says, "there is a whole lot
of activity packed into this little board."
Students use mathematical, graphing, graphing calculator, spreadsheet
and critical-thinking skills to make sense of the data collected during
the various board activities. For example, students use graphing calculator
curve-fitting techniques to verify the reactance formulas. Drawing on
the
premise that one picture is worth a thousand words, Spencer says, spreadsheet
software helps students visualize the raw voltage and current data measurements.
During the DSP activities, students use the OptaScope digital oscilloscope
to see the stair-step waveform generated by the computer and the DAC on
one channel, and the smoothed waveform exiting a simple filter on the
other. "Visualizing a waveform in discrete slices helps students
understand what happens during DSP," Spencer explains.
The L/C/R activity board kit includes the circuit board, the parts to
populate it, plus documentation to support the board's construction and
use. As with previous activity boards, this one is designed to be constructed
by students under adult supervision.
Activity board kits are available to interested and qualified schools
through generous donations to the Education and Technology Program Fund.
To qualify for one of these kits, interested schools need to write to
Spencer on school letterhead and verify that (1) the lead teacher has
reviewed the curriculum that supports the L/C/R activity board, (2) the
curriculum and the board fit into the school's curriculum and the school
intends to use
the board as an instructional activity, and (3) the school has the capability
to build the activity board (preferably, students will do the actual construction).
For schools wishing to roll their own, all documentation, diagrams, a
parts list, and software in hard copy are available simply for the asking.
Send requests to Mark Spencer, WA8SME, ARRL, 225 Main St, Newington, CT
06111.
Another new activity board kit, to be available in January 2005, is a
simple and inexpensive direct-conversion receiver kit, produced by the
American QRP Club.
For more information about these boards and the ARRL Education and Technology
Program, contact Mark Spencer, WA8SME, 860-594-0396; mspencer@arrl.org.
To learn more about how to support the ARRL Education and Technology
Program, contact ARRL Chief Development Officer Mary Hobart, K1MMH, 860-594-0397;
mhobart@arrl.org.
Source: ARRL Letter - courtesy of The
American Radio Relay League
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