The 50th Anniversary of the First Visible Light LED

Masterclock digital clocks and a 30" analog clock

Several Masterclock digital clocks (at right) and a 30″ analog clock (at left) on a rack ready for display at the next electronics convention.

The LED (light emitting diode) has been around for 50 years. And for most of those years they’ve been lighting up Masterclock digital clocks (see image at left).

The University of Illinois recently celebrated the 50th anniversary of the invention of the visible spectrum LED and its inventor, Professor Nick Holonyak Jr.

Top scientists from around the world paid homage to Dr. Holonyak recently in a symposium held October 24 and 25, 2012 at the Urbana-Champaign campus of the University of Illinois where the professor has been since 1963. This is only the latest of many honors Dr. Holonyak has earned in his career.

Back in 1962…
Within two decades after the invention of the transistor in 1947,  LEDs were being produced, but they were only capable of emitting infrared light, otherwise known as invisible heat. In 1962 young Holonyak, then working for a General Electric research lab in New York state and just out of grad school, mixed gallium arsenide and gallium phosphide to create the first diode that could produce visible light. Unfortunately, the practical benefits of his invention had to wait several years before they were more fully appreciated and commercially available.

Holonyak calls the LED the “ultimate lamp.”
The electrical current itself generates light, rather than heating a filament, making the LED fast, efficient and affordable. At first the only color was red. Today, LEDs come in every color and can be found in low-tech and hi-tech products, serving the world and lighting up kids’ toys. In the February 1963 issue of Reader’s Digest Holonyak predicted that LEDs would someday replace the incandescent light bulb of Thomas Edison. Unfortunately it took fifty years for that idea to catch on.

Pulsar Watch, ca. 1972,

Pulsar Watch, ca. 1972, now worth more than 10x its original price of $2,100.

LEDs and Time-Keeping
In 1972 watch manufacturer, Pulsar, introduced the first LED watch. Dubbed the Time Computer, the watch was said to be accurate to within 60 seconds a year. It cost $2,100 at the time. because it was the first to utilize LED technology in a small package and it relied on electronics to tell the time. Unfortunately, all this new technology devoured battery-life, which is why the watch required the wearer to press a button to see the time only when he needed to.Red
The first LEDs were red. This wasn’t a choice.  Blame it on physics. LEDs are created by layering semiconductor crystals on a tiny wafer. As layers are added, dopants (trace impurities) are also added to  color the LED. Gallium arsenide phosphide was the original dopant and it creates a natural red color when electrified.

New processes and new elements create all the colors of the rainbow in today’s LEDs.

In 1993 Shuji Nakamura invented the bright blue LED using gallium nitride.

Blue LEDs coated with yellow phosphors provide white light. This was also a Nakamura invention.

A Mastercock TCDS8646 with a row of red LED digits over a row of smaller amber LEDs.

A Mastercock TCDS8646 digital display with a row of red LED digits over a row of smaller amber LEDs.

Masterclock designs and makes digital clocks in a wide variety of sizes and types using red, green, blue and yellow digits. You can mix and match them in some of our larger clocks. They portray the day, date, the day of the year and can even perform countdowns and provide alphanumeric messages.

If you’d like to learn more, come visit us soon at

Time is important. That’s why we’re in this business.

This blog is brought to you by Masterclock, Inc. We design, build and sell a large catalog of professional-quality digital and analog clocks, master clocks, network clocks, time code clocks, time code generators and other synchronized time devices for precise applications at an affordable price.

If you have any questions about time, GPS, digital clocks or any other subject you’d like to know more about, sent them to us. We’ll be happy to reply directly and post answers.

Come visit us at!


A Note from Hollywood: The Clapperboard and SMPTE

This is a modern SMPTE clapperboard

This is a modern SMPTE clapperboard with synced TIme Code. Here we’re about 18 and a half seconds into the production. We’re looking at frame #13 of 30 per second in the last column. That frame rate is too fast for the human eye to follow, so Masterclock clocks never show the frames, even though many of our clocks are referenced to the SMPTE frame rate.

Rolling. Speed. Take One. [SNAP] And… Action!
The clapperboard is a staple of Hollywood. In the old days, when movies were shot on film and the sound was captured on tape, a simple snap of the clapperboard and a chalked out note on its face were the ways moviemakers synced sound with picture back in the editing room.

Traditional clapperboards consisted of a wooden slate and a hinged clapstick attached to the top of the slate. Today, smart slates, or digi-slates, are electronic SMPTE Time Code versions with LED numbers (shown above). They mark the hour, minute, second and frame (1-30) of a production so lip-sync editing has never been more precise.

30 Frames per Second
If you ever get a chance to see one of these SMPTE clapperboards in action, you’ll notice the human eye cannot follow the speedy rounds of thirty frames each second. It goes by in a blur. But the camera, shooting each picture at 1/30th of a second sees these frames clearly and in order. Then again, high speed cameras (that project in slow motion) see each number on the clapperboard for several frames before the next one appears. It’s all a matter of your time frame.

For today’s blog we’re interested in SMPTE Time Code as it pertains to the digital clocks and analog clocks produced by Masterclock that rely on Time Code for their sync reference.

SMPTE Time Code
is a set of standards to label individual frames (1 through 30 for each second of video) with a Time Code defined by the Society of Motion Picture and Television Engineers (or SMPTE for short).

Time Codes provide an embedded time reference for editing, synchronization and identification. The invention of Time Code made modern videotape editing possible, and is still in use in today’s digital cameras. Those who buy Masterclock clocks with a Time Code (SMPTE or IRIG) reference generally use them in the broadcast industry where everything is edited by the second and the frame. Others who buy Time Code products may be locked into legacy systems built before the 1990s when NTP (Network Time {Protocol) and GPS satellite reference systems became more available and popular.

NTP is the Latest Thing. 
The competing system, NTP (Network Time Protocol) arrived with the Internet and it is growing in popularity. NTP utilizes standard Ethernet wiring to synchronize computers, clocks and other network devices to a NTP reference server, typically ultimately synced to atomic clocks aboard GPS satellites. Besides the increased accuracy, another benefit to NTP is the same wire that carries the signal can also carry the power needed to run the clock, so wiring is simplified. This is called PoE (Power over Ethernet) and it is also becoming more popular.

No matter what your precise synchronization needs are, Masterclock is as close as our website. Let us know if we can help you with your upcoming projects.

Time is important. That’s why we’re in this business.

This blog is brought to you by Masterclock, Inc. We design, build and sell a large catalog of professional-quality digital and analog clocks, master clocks, network clocks, time code clocks, time code generators and other synchronized time devices for precise applications at an affordable price.

If you have any questions about time, GPS, digital clocks or any other subject you’d like to know more about, sent them to us. We’ll be happy to reply directly and post answers.

Come visit us at!

Fun Facts About Time Zones from Masterclock

 A map of the Earth divided into Time Zones

Figure 1. The official Time Zone chart from the Central Intelligence Agency, USA. You may need to refer to this while reading the text unless you are an excellent student of geography. Click to enlarge.

Time is Based on the Sun
Every day the sun travels from the eastern horizon to the western horizon*. At its zenith the sun crosses the North-South line. At this point, local noon time, the shadows are the shortest as the sun is more or less directly overhead, depending on your location on the planet and the time of year.

Figuring out the diameter of the Earth in ancient times
At certain well-placed water wells between the Tropic of Cancer and the Tropic of Capricorn, on certain days of the year, the bottom of the well is illuminated by a beam of light coming from the sun passing directly overhead precisely at noon. In other wells, elsewhere on the planet, on the same day at the same time, the beam of sunlight does not reach the bottom of the well, but comes in at another angle. That’s how certain ancient thinkers reasoned that the world was round since all the wells pointed directly down, toward the center of a globular Earth. With their data they were able to pretty closely figure out the Earth’s diameter through simple geometry.

An infinite number of noons every day
Now, if you think about it, a gradually moving sun produces an infinite number of local ‘noons’ every day around the world. Of course, until recently, that was never a problem. In the old days, no one was on a schedule and there were no good clocks around to put us on a schedule. So no one really cared what time it was. All we had to do was to get up with the sunrise and sleep after the sun had set.

Railroad train schedules
That all changed when the railroads came along. They had a schedule to keep to maximize their fares. They didn’t want any of their passengers to arrive late and miss the train. So the railroad tycoons came together and devised their own Time Zones: over 100 across the USA alone. Unfortunately, one hundred Time Zones were way too many. So in 1883 the USA was divided into four official Time Zones (see fig. 1). Suddenly everything became more manageable! Following that success, an international consensus for global Time Zones was introduced in 1884 and the results are also shown in figure 1 above.

Pocket Watches and Alarm Clocks
Keeping up with trains, meant people had to be on time. And businesses opened and closed at certain precise times. From then on everybody had to be to work on time, travelers had a train schedule to meet, and everyone had to buy their own clock or a personal pocket watch to keep pace with their busy scheduled world.

The ideal and the compromise
That previously mentioned international consensus divided the Earth into 24 longitudinal slices (from pole to pole), each 15 degrees in width, one for each hour of the day. Within each Time Zone all clocks were to be synchronized to the same hour, minute and second. Just outside of each zone – ideally – time would have been exactly one hour earlier or one hour later, depending on your directions of travel, west or east.

But that’s not how it happened to work out.

Setting the Prime Meridian
Due to English dominance at the time, and the fact that the antipodes were over the Pacific and Australia, that international consensus placed the Pime Merdian at Greenwich, England. So, when it is noon at Greenwich it is midnight and the start of a new day at the International Date Line on the opposite side of the Earth. All other Time Zones exist between these two and all other official Time Zones are referenced to these two imaginary lines running from pole to pole on opposites side of the Earth.

Zulu Time
Every Time Zone has a distinct letter code. England is at Zulu time. Only Portugal, Iceland and Western Africa share Zulu time.

Atomic clocks on GPS satellites reference Zulu time (UTC) to computers and other devices worldwide. Masterclock products read these signals to synchronize electronic devices with GPS satellites and other linked devices around the world.

Alpha Time
You might think that Spain would be on Zulu time since it is directly south of England. Not so. Nearly all of Europe is one hour later on Alpha time. So is a swath of mid-western Africa with country boundaries forming most of the eastern and western margins of the Time Zones.

Bravo Time
Finland and the Baltics, the Ukraine and eastern Europe, much of the Middle East, and a swath of southern Africa are on Bravo time. Libya lies completely within Alpha time, but joins Egypt in Bravo time. Between Chad and the Sudan there is no Bravo time, so a trip from one to the other requires a two-hour resetting of your clock.

Charlie Time
The Sudan is completely within Bravo time, but joins its eastern neighbors comprising the horn of Africa in Charlie time. In Europe only Belarus and a little land surrounding the Russian seaport of Kalinigrad are on Charlie time. Iraq, Saudi Arabia and the island of Madagascar round out this Time Zone memberhship.

Delta Time
The portion of Russia surrounding Moscow is on Delta time, despite the fact that most of this area is in Charlie time. Oman is the only other country on Delta time.

Echo Time
Kazakhstan and neighboring countries, including Pakistan, are on Echo time even though most of the area lies within Delta time. Iran splits the difference and sets its time a half-hour earlier than its neighbors. Afghanistan and India set their time a half-hour later.

Foxtrot Time
Virtually none of the areas that use Foxtrot time are actually in Foxtrot time. These include the west-central areas of Russia. However, tiny Bangladesh and Nepal use and are completely within Foxtrot time. Burma is a half-hour later. Nepal, breaks all the ‘rules’ and is 15 minutes earlier than Foxtrot time.

Golf Time
Southeast Asia is on Golf Time. So is a Russian province west of Mongolia surrounding Novosibirsk, even though it is largely two Time Zones away in the Echo zone.

Hotel Time
A strip of central Siberia (Russia) and all of Mongolia and China, the Philippines and western Australia are in Hotel time. China spans four time zones, but synchronizes the whole country under the one zone based on their more populated eastern seaboard.

India Time
The portion of Siberia (Russia) surround Irkutsk is on India time, even though that area is geographically two Time Zones away in Golf time. Korea and Japan are both on and within India time, sharing it with the western half of the island of New Guinea.

There is no Juliet Time.

Kilo Time
The portion of Siberia (Russia) north of eastern China is on Kilo Time, even though it is largely over Hotel time, two Time Zones away. So is eastern Australia and New Guinea. Central Australia is a half-hour earlier.

Lima Time
A slim strip of Siberia (Russia) north of Valdivostok is on Lima Time, although geographically it is largely over India time. Here, if you fly south into Japan, it will be two hours earlier.

Mike and Yankee Time
With the International Date Line things get a little crazy. Eastern Siberia (Russia) and New Zealand are on Mike Time, along with a few south sea islands. For some reason the alphabetical pattern shifts here and goes to Yankee, which contains, as far as I can tell, no land areas. As we continue going East the Alpha order reverses (from Y to N) as you’ll see.

The International Date Line
Between Mike time and Yankee time is the International Date Line (IDL). When it is noon at Greenwich, England, it is midnight at the IDL and the beginning of a new day. One hour later only fifteen degrees of the Earth is in that new day. That’s why, whenever you cross the International Date Line going West, you enter that next day. And here is your only chance to go back in time, by one day, by flying east over the IDL. Only exactly at midnight at the IDL is the whole world experiencing the same day. Part of the IDL juts east over three Time Zones to encompass several Pacific island chains.

X-ray Time
Just a few Pacific Islands are on X-ray time. It is largely oceanic and therefore less affected by poltical lines.

Whiskey Time
The westernmost Aleutians, Hawaii and the islands of French Polynesia are on Whiskey time. Hawaii does not follow Daylight Savings Time, so they are one hour earlier than the rest of Whiskey time in summer.

Victor Time
Virtually all of Alaska is on Victor time even though the bulk of Alaska is in the Whiskey and X-ray zones.

Uniform Time (Western Time Zone in the USA)
Western Canada and the West coast of the USA is in the Uniform Time Zone, along with the tiny Pitcairn Islands in the South Pacific.

Tango Time (Mountain Time Zone in the USA)
The Rocky Mountain States are in Tango time. Arizona is too, but does not observe Daylight Savings Time.

Sierra Time (Central Time Zone in the USA)
The central plains of Canada, the USA and most of Mexico and Central America are in Sierra Time.

Romeo Time (Eastern Time Zone in the USA)
Eastern North America and western South America are on Romeo time.

Quebec Time
The tiny, easternmost provinces of Canada are on Quebec time. So is a swath of South America from western Brazil to Chile. Venezuela is a half hour earlier.

Papa Time
Much of Greenland, eastern Brazil and Argentina are on Papa time, even though Argentina straddles Romeo and Quebec time. Why the westernmost and easternmost tips of Greenland are not on Papa time is anyone’s guess. Almost no one lives there and most of those few don’t carry watches and there are no trains to catch! Tiny Greenland straddles five Time Zones, but that’s because the Time Zones converge near the poles. Newfoundland is a half-hour earlier.

Oscar Time
Virtually no land areas are covered by Oscar time, although eastern Greenland occupies it.

November Time
Only a few Atlantic Islands, including the Azores, are on November time.

But Wait, There’s More!
As you can see, politics, as much as the postion of the sun, plays a part in determining the boundaries of Time Zones and the local time. Only across vast stretches of open ocean are the Time Zone lines more or less straight from pole to pole, as they should be.

Where All the ‘Rules’ Go Out the Window
Everyone knows, if you walk around the North or South Pole, you can cross all 24 times zones in less than a minute, because all the Time Zones converge at those points.* A little further south, across northern Siberia, there is another two-hour jump between Time Zones. As in the Sahara (see Bravo time, above), with so few people and such a harsh environment, nobody is complaining.

If you have a computer or a clock and you want it to display precise local time, whatever your Time Zone, Masterclock can provide you with the system to do so. From GPS antennas, to signal readers, master clock generators and digital clocks of all sorts, Masterclock products read UTC from GPS satellites and configure for local time, with and without daylight savings, automatically. Our products are in use around the world, bought by the smallest and largest corporations and organizations on the planet.

Time is important. That’s why we’re in this business.

This blog is brought to you by Masterclock, Inc. We design, build and sell a large catalog of professional-quality digital and analog clocks, master clocks, network clocks,Time Code clocks, Time Code generators and other synchronized time devices for precise applications at an affordable price.

If you have any questions about time, GPS, digital clocks or any other subject you’d like to know more about, sent them to us. We’ll be happy to reply directly and post answers.

Come visit us at!

*At the poles, of course, things are different. The sun simply goes around the horizon, never rising more than 23 degrees (the tilt of the Earth). For half the year the sun remains below the horizon casting a perpetual twilight glow during the spring and fall and creating days without sunshine for the winter or summer months, depending on the pole you happen to be on.

Welcome to The Masterclock Times

In a world demanding ever more precise synchronized time,
our professional digital clocks and other devices are synchronized to atomic clocks in GPS satellites and other synchronized Time Code sources. For most applications, from broadcasting to law enforcement, you can’t do better than that.

Masterclock, Inc. logo

The Masterclock logo. Your guarantee of a quality precision clock that performs to spec. Click to go to

What to expect
This blog is intended to demystify various aspects of time keeping and synchronization. We’ll take you behind the scenes of various businesses and institutions that currently use our devices and clocks. We’ll look at time keeping in the past and we’ll look forward to an even more precise future, starting tomorrow!

Who we are
This blog is brought to you by Masterclock, Inc. We design, build and sell a large catalog of professional-quality digital and analog clocks, master clocks, network clocks, Time Code clocks, Time Code generators and other synchronized time devices for precise applications at an affordable price.

Humble beginnings. Today an important player.
What started as a prototypical ‘business in a garage’ several decades ago, Masterclock today has grown to become an important player in the digital clock market, with sales to major corporations both domestically and internationally. You’ll find our devices in airports, broadcast studios, law enforcement agencies, military installations and government buildings. Corporate campuses and sports arenas are some of our best customers.

Send us your questions
If you have any questions about time, GPS, digital clocks, NTP, Time Code or any other “timely” subject you’d like to know more about, send them to us. We’ll be happy to reply directly and post the answers.

Come visit us at! And we look forward to your future visits.