Test Your EQ
— Issue #160
Each month, Test Your EQ presents
some basic engineering problems for you to test
your Engineering Quotient. What's your EQ?
|
Problem
1—While
browsing some C code, you come across an aaa.h file, which
contains the following lines:
GLOBAL int aaa_function1();
GLOBAL int aaa_function2();
The corresponding aaa.c file includes the following:
#define GLOBAL extern
#include "bbb.h"
#include "ccc.h"
#undef GLOBAL
#define GLOBAL
#include "aaa.h"
What is the purpose of the GLOBAL
symbol?
Answer
Problem
2—What is the Curie point of a material?
Answer
Problem 3—How can this be used to regulate
temperature of, say, a soldering iron?
Answer
Problem
4—A certain kind of spectroscopy requires that
an AC voltage in the range of 1 to 25 kHz at 2 kVRMS be
applied to a capacitive load of about 1 nF. How much power
does the power supply need to deliver? How much current?
Answer
Problem
5—A board designer lays out a 50-W
microstrip transmission line across the top surface of
his board between a connector and a 50-W
terminating resistor. The line passes underneath a patch
of white paint used for writing a lot number on the board
during manufacturing. When tested using a TDR, reflections
are observed at the edges of the paint. Why?
Answer
Problem
6—I really hate these four-band, color-coded
resistors. I have a batch of eight, all of which have
the same color markings (1 kW).
I know that one of them is either shorted or open, but
I don't know which. I also have an ohmmeter, but its batteries
are extremely low, and it has only enough charge to make
two resistance readings. How can I pick the odd resistor
out of the eight with only two ohmmeter readings?
Answer
Problem
7—What if the resistor is not completely shorted
or open, but just off by some factor (too low or high).
What is the minimum error that can be unambiguously detected
by the previous solution?
Answer
Problem
8—I have a network cable connecting two rooms.
The cable consists of 10 wires in a single conduit (tube).
All of the wires have white insulation, and I cannot tell
which is which. The only tool I have is a continuity tester.
What is the least number of trips backwards and forwards
between the two rooms I need to make in order to identify
which wire is which?
Answer
Published November 2003
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