ELE Times December 2016 Electronics News in India | Online Electronics Mag | Page 44

Technology
electrical energy, the vibrations of machines, engines, musical
instruments, and timepieces may be analyzed. Metals may be
tested for composition and characteristics by observing their
magnetic or electrical behavior when subjected to high-frequency
fields.
The usual method of measuring the speed of a rotating machine
was to stick a mechanical tachometer or revolution counter
against the end of the shaft. In the case of a very small motor, the
tachometer load might be enough to slow it down. With highspeed machines, the method was likely to be inaccurate because
of slippage. By means of an electronic stroboscope using a light
flashing at a known frequency, the speed of a rotating object may
be measured accurately without contact.

Electronically Controlled Music
Advance features: With the progress in the use and features
provided by the smart phones, life is going to be affected by
electronics in many ways in the times to come.
Control manufacturing operations: We now know how to control
manufacturing operations with superhuman accuracy, how to
assemble materials with amazingly precise methods of welding,
and how to run motors at infinitely varying speeds to suit each
changing phase of machine operation and that too automatically.
Electronic measurements: Electronic measurements may deal
with quantities inappreciable except by almost incredibly
sensitive instruments or as great as the distance of a star from the
earth. They may soar out into space or burrow into the earth.
Mapping: In scientific exploration for oil, dynamite is exploded in
a shot hole, setting up a small artificial earthquake. Suitably
disposed pickups, designed to convert earth vibrations into
electrical vibrations, respond to the reflections from the
underlying rock strata. The outputs of the pickups are amplified
electronically and recorded as seismograph traces, which permit
mapping substrata as deep as 20,000 feet.
Measuring: Nowadays, machine parts are commonly made with a
tolerance of less than a ten-thousandth of an inch. Length,
thickness, speed, time, mass, illumination, chemical composition,
electrical quantities are all measured with an accuracy of only a
few parts in a million, and usually we find electronic or semielectronic devices doing the measuring. An example of a wholly
electronic measuring instrument is the cathode-ray oscillograph,
called “the most versatile measuring instrument ever devised by
science. The operating principle of the cathode-ray tube is the
deflection of an electron beam by electrodes in the neck of the
tube, to which an unknown variable voltage is applied.
Functioning as a weightless pointer, the beam traces a curve on a
fluorescent screen, which shows how the voltage varies with
time. The magnitude and duration of welding currents, the
behavior of electronic motor controls, and of every other
electronic or electrical machine, can be studied in the utmost
detail. By using some form of pickup to convert mechanical into

Electronic control: The new technique of resistance welding
requires electronic control. The process consists in joining metal
parts by pressing them together mechanically, sending an electric
current through the joint, and then shutting off the current and
maintaining the pressure for another instant while the molten
metal “freezes.” Any deviation may mean the difference between
a perfect weld and a poor one. Some types of precision resistance
welding are actually done in a fraction of a cycle, and it has to be
the same fraction each time, in the same part of the cycle.
Making and breaking currents of this magnitude is a ticklish job,
and it has to be done automatically hundreds of times a minute.
About the only kind of switch that measures up to the job is a
frictionless and inertia less device in which small amounts of
power can control large amounts in short, an electronic device.
Induction heating: Induction heating, a comparatively new
method of applying heat in industrial operations, has also
contributed materially to manufacturing, and promises to play a
significant part in electronics. With electronic methods, heat may
be produced within the material, so that, if desired the whole
mass can be kept at a uniform temperature throughout the
process or with equal ease, electronic heat may be applied
selectively.
Conversion: In the development of mercury-arc and other
electronic rectifiers for large-scale conversion of AC into DC, we
see one of those long-term swings in technological history that
color the lives of millions. The availability of convenient and
efficient rectifiers, in turn, encourages industrialists to use DC
equipment for many other purposes. So DC and electronics, in
partnership, are going places. Even in the field of long-distance
power transmission, in which AC has reigned unchallenged for

ELE Times | 44 | December, 2016