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June 1958 Popular Electronics
 Table of Contents
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.
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Some things never change
- at least at the fundamentals level. Electric circuits is one of those things.
I don't remember when I first became interested in electrical apperati, but it
must have been due to a natural affinity to the science because nobody in my
family or my circle of friends expressed any interest. I was the odd man (or
boy) out on my street, because while all the other kids were playing baseball,
basketball, and football, I was sticking forks in electric sockets and
disassembling flashlights, battery-powered toys, and building
Erector Set contraptions using the included electric motor. That's not to
say I ever got really good at it, but significantly better than I ever got at
playing sports. This 1958 Popular Electronics magazine article promotes
the introduction of electrical concepts to young kids in hopes of instilling a
lifelong interest in the subject. BTW, the glasses on that nice lady may just
have been the inspiration for the kind drawn by "The Far Side" comic artist Gary Larson.
Teach Kids Electricity
Easily assembled "power plant" shows electrical facts of life.
By John Hoke
"Daddy," what makes the light bulb light? ..."
Thus begins an era for many a young father, for this sentence is but the first
trickle of what will later become a waterfall of questions, as a small boy learns
that there is more involved than just flicking on the switch. When dealing with
an elusive entity such as electricity, the most effective means of describing what
it is consists of a simple way of showing what it does.
Seeing Is Believing
Here, on a short length of planking, are the ingredients of a small power plant
capable of doing amazing things. It will make electricity - at the turn of the crank.
It will provide high or low voltages, at the flip of a switch. It will store electricity.
It will light a 117-volt, 10-watt light bulb or run a small, 6-volt motor. It will
operate a transistor radio or an electric clock. And it will yield current in small
enough doses to permit feeling it - without discomfort.
For a small boy, next to putting a coin in a gum machine, there is no greater
urge than to turn a crank. It won't take long to get the idea across that he is
making the bulb light - or the motor run - when he turns the crank. And when he
first feels the current generated, he will realize that his crank - turning makes
"something," and that this "something" in turn flows through the circuit to the
motor and makes it run. From here on, step by step, his understanding of this invisible
force will increase.
A useful by-product of the child's self-education is a healthy respect for the
power of electricity. He soon becomes aware of the shocking potential of wall outlets
when a few turns on his little generator make its current uncomfortable to touch.
On the Board
Hand generator mounted on plank with one of the gadgets that
can be powered by it.
Schematic shows one possible hookup described in text.
Assembly is not overly complicated. Most of the components which are mounted
on the plank should be locally available and only the generator need be obtained
by mail.
The generator is actually the same type of bell-ringing mechanism used in rural
telephone systems years ago. Having a maximum output of about 100 volts, a.c., such
generators are currently available from firms like Johnson Smith Co., Detroit 7,
Mich., for approximately four dollars. No modifications are necessary; they are
ready to operate as is.
The output of the generator is fed to the center posts of a double-pole, double-throw
knife switch (S1). One side of the switch is connected to a conventional socket.
This will permit connecting a number of devices, including a 10-watt light bulb.
You'll need a step-down transformer line voltage to about 6 volts is the proper
size. A bell transformer will do fine.
Primary leads of the transformer go to the remaining terminals of the knife switch,
and hence to the output of the generator, when switched in. The secondary feeds
through the rectifier and then to the binding posts that will serve as an outlet
for devices. The rectifier can be any low -voltage type with adequate current
rating, such as International Rectifier M1H.
Current on Tap
To store current, you will need a small storage cell. The Willard 2-volt types
are useful in this application.
When hooking up a circuit to utilize one of these cells, it is a good idea to
incorporate an s.p.s.t. knife switch (S2), so that the cell can be switched in and
out of the circuit whenever circumstances dictate. You can then run the motor directly
from the output, or you can switch in the battery with the motor to charge the cell
and run the motor simultaneously. The motor's continued running when the generator
is stopped will illustrate the fact that power was stored in the battery - and is
yielded when the supply from the generator and transformer ceases.
If you wish, you can charge the battery alone, with the generator, and run the
motor on the stored current by opening and then closing another s.p.s.t. switch
(SS). Other variations are also possible.
As an example, the small motor shown mounted on the board is hooked up to a miniature
water fountain. Motors such as the Mighty Midget (Lafayette F253) can be used in
innumerable mechanical hookups.
With the complete setup, you have an impressive transference of power. The chain
goes from initial mechanical origin to generation, transformation, rectification,
storage and consumption by motor ... all at the turn of a crank, with a one boy
- power source of energy! This is the foundation for a course in electricity and
its applications, tailor - made and contained on a short pine board.
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