Wax nostalgic about and learn from the history of early electronics. See articles
from Popular Electronics,
published October 1954 - April 1985. All copyrights are hereby acknowledged.
This electronics analogy
quiz is a little easier than many of the others published in Popular Electronics
magazine
because all of the electrical and mechanical objects depicted here are very familiar.
The concepts might seem trivial to those of us who have been immersed in the science
for decades, but I for one can remember when first hearing these analogies how helpful
they were. Not only that, but I also recall during physics and mechanics courses
in college being amazed at the similarity of equations shared by electrical and
mechanical processes. Wikipedia has a huge page describing many of the most
familiar
mechanical-electrical analogies.
Electronic Analogy Quiz
By Robert P. Balin
Analogies - or comparisons - between electrical and mechanical phenomena are
widely used to explain many electronic principles. See if you can match the lettered
objects to the numbered symbols in the boxes below. The correct match in each case,
and a complete explanation of the principles involved, will be found at the bottom
of the page.
Quizzes from vintage electronics magazines such as Popular
Electronics, Electronics-World, QST, and Radio News were published
over the years - some really simple and others not so simple. Robert P. Balin
created most of the quizzes for Popular Electronics. This is a listing
of all I have posted thus far.
I. G. Because of its magnetic field, an inductor has the ability to resist any
change in the amount or direction of the current flowing through it - we call this
property "electrical inertia." A heavy grinding wheel, because of its mass, has
mechanical inertia and tends to resist any change in its speed or direction of rotation.
2. D. A rectifier in an electrical circuit permits electron flow in only one
direction. A ratchet wheel and check pawl likewise permit rotation in only one direction.
3. C. A capacitor stores electrical energy in its dielectric when it is charged,
and the energy is recovered when you provide a discharge path for it. The coil spring
in a jack-in-the-box stores mechanical energy in its stressed turns when the spring
is compressed; this energy is recovered when you open the box.
4. H. A fuse element can carry little more than the normal current for its circuit;
when an overload occurs, it is the first thing to burn in two and thereby open the
circuit. The fuse may be compared, then, to the weakest link in a chain.
5. B. A resonant circuit will oscillate at a frequency determined by the inductance
and capacitance present. A tuning fork oscillates as well, but at a frequency determined
by its mechanical construction.
6. A. A transformer takes electrical energy supplied to its primary winding as
a large current at low voltage and provides us with virtually the same amount of
energy delivered as a small current at high voltage from its secondary winding.
A gear train receives mechanical energy at high speed and low torque and converts
it for use by a device requiring the same amount of power supplied at low speed
and high torque.
7. E. An open switch stops electron flow in the same manner as a closed faucet
stops the flow of water.
8. F. A resistor limits the current in a circuit, but converts some of the electrical
energy into heat while doing so. The brake shoe on the wagon wheel limits the speed
of its rotation, and changes some of the mechanical energy into heat.
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