October
2004, Issue 171
Test Your EQ
Each
month, Test Your EQ presents some basic engineering
problems for you to test your Engineering Quotient.
What's your EQ?
|
Problem
1—What
is the load current ILOAD in the following
circuit if R3/R2 = R4/R1?
Answer
Problem
2—What is the load current ILOAD in
this other circuit if R3/R2 = R4/R1?
Answer
Problem 3—What are some of the advantages of
the second circuit over the first? Hint: think about some
of the characteristics of nonideal components.
Answer
Problem
4—Frugalson has a simple voltage measurement
and serialization application. The budget only affords
a 12-bit ADC and a $2 MCU for conversion and control.
The 12-bit binary ADC has a full range of 0 to 10 V, and
the serial packet formatting must be in decimal in units
of 0.01 V. One day, before the deadline of the project,
Frugalson realizes that the MCU has no C language support,
let alone floating-point libraries. Should Frugalson start
to update his resume?
Answer
Problem
5—It has been proposed that small robots could
navigate in a relatively confined space by setting up
a rotating optical beacon. This beacon would rotate at
about 60 radians per second (approximately 9.55 Hz, or
573 RPM) and broadcast a “fan” of laser light that is
fairly broad vertically, but extremely narrow in the horizontal
plane for good resolution. The omnidirectional sensors
on the robot would output a pulse when the light passes
them, but provide no information about the direction from
which the light comes.
What
basic fact do you learn about the geometry of the situation
by comparing the pulses from two different sensors?
Answer
Problem
6—After you know the basic fact about the geometry
of two sensors and the beacon, what can you say about
the overall relationship between the beacon and the robot?
Answer
Problem
7—Let’s assume that the sensor spacing on the
robot is approximately 10 cm, and that the arena in which
it operates is a circle with a 10-m radius centered on
the beacon. What kind of timing resolution is required
in the sensors?
