Top ten electronic inventions that are older than you think

Top ten electronic inventions that are older than you think

Consider a modern, mobile phone and all that’s inside it: electronics, touch screens, computer-in-your-palm, internet connection, games, gadgets, sensors, etc.
Revolutionary, isn’t it. Or?

In this post I have dug up some older patents/publications/products with respect to all these things in the phone – but were already out there – quite a while ago – in some form. Now, some of these examples are up to a discussion, of course. There is even older, prior art here and there, and there are also certain inventions that (p)laymen could have realized quite easily and thus the origin could be discussed.

One can also argue about terms like electrical vs electronic vs electro-mechanical, but let us leave that discussion for now.

The electric filter, 1915

Filters are key components in most circuits and systems. Filtering out noise, interferers, select channels, etc. So, when was the first electrical filter used? Quite long time ago and probably even before Doctor George Campbell at the AT&T published his two patents on electric filters in 1915. He proposed in patent US1227113 the electric wafe-filter consisting of the ladder networks that are so widely used today.

In patent US1227114 he proposed the filter as a way to protect equipment by filtering out components at different frequencies.


The first flip-flop, 1918

I posted about the first flip-flop before and it is fascinating, almost exciting, that we soon celebrate 100 years of flip-flops, or so…

So, back in 1918, the researchers realized that they could take a set of “ionic relays” and connect them such that they can remember previous states they have been in.

You can read the original patent and find a picture like this.


Here we find more or less a regenerative latch, a flip-flop, invented by FW Jordan and WH Eccles. Mr. Eccles did quite a lot of other things too with respect to early electronics. I encourage you to do a bit of researching there.

The Miller effect, 1920

I am putting the Miller effect into the picture here as it is kind of crucial for analog design, especially amplifier design. It is not an invention as such, but rather a pretty direct conclusion from the maths given that we have a set of stages that provide gain.

The Miller effect states that capacitance is amplified by (approximately) the raw gain of the stage over which the capacitance is connected. This is for good and bad. It can be used to efficiently compensate a system to improve phase margin, but it will also inevitably increase the effect of (undesired) capacitive components.

The concept is valid for any impedance/admittance, but a resistance/inductance would decrease by the gain instead. For inductors and resistors the use is perhaps of less interest, whereas area can be saved for capacitors as it effectively multiplies the capacitance.

John Milton Miller published material in 1920 on this effect, but then using vacuum tubes rather than transistors.

  • J. M. Miller, “Dependence of the input impedance of a three-electrode vacuum tube upon the load in the plate circuit,” Scientific Papers of the buerau of standards, 1920

2014-07-02 13.02.00

The phase-locked loop, 1921

Another important building block in your electronic devices is the phase-locked loop (PLL). It allows you to adjust, or multiply, or divide, what have you, a frequency or a clock. Dependent on the accuracy of the hardware you can transform one frequency into more or less any other. This is of course useful in modern systems where you want to minimize the number of reference clocks to a single one and then, from that, derive all other internal frequencies required to drive the radio, display, microcontroller, CPU, GPU circuits, and many more.

So, when did the first PLL pop up? In 1921 the amazingly accurate Shortt synchronome clock (it was accurate to 1 second within 12 years of ticking!). It used a reference clock at lower speed to tune the main clock and by adding a little push or a gentle stop on the main pendelum (similar to a charge pump after the phase detector!) it adjusted the main clock. So, a more accurate lower-speed clock could be used to tune a higher-speed one. Beautiful.

The transistor, 1926

The field-effect transistor, more or less the father (or mother …) of all CMOS transistor we see today in the microchips we remember from Shockley’s work, etc.
But actually, the FET was patented some 20 years (!) before that by Julius Edgar Lilienfeld.


By then, however, the material science had not advanced enough to make it possible to physically implement them. This was the advance by Shockley and the traitorous eight. And the rest is history.

Electronic games, 1936

Did you know that the first electrical/electronic arcade game showed up already in 1936?

It was was called ray-o-lite and was produced by a company called Seeburg. In the game you shot down ducks with a light gun (well, a rifle). A mechanical bird “flew” over the arcade carrying a light sensor.

Light would be emitted once you pull the trigger on the rifle and if you aimed correctly, the light detector tube on the bird would trigger and eventually alarm a bell.

I have below borrowed a picture from Pinrepair which shows the duck on its way as well as a counter on the tap. Visit their page for more information.

The first electronic computer, 1942

Now, a definition “computer” is a bit vague and there are older computing machines as such. The first computer is traditionally said to be the ENIAC computer, but since 1973 it was decided that the patent for an electronic computer went to the inventors of the Atanasoff–Berry computer (ABC) and not the inventors of ENIAC (who filed a patent after the ABC was finalized in 1942).

It is now 72 years since the ABC was first operational and in the 90’s they built a replica of the computer and is on display. See below.

As a side note, the ENIAC was based on decimal arithmetic, while the ABC was binary.

User interfaces, the touch screen, 1965

In terms of user interfaces, or perhaps more correctly: human-machine interfaces, we are now slowly going away from the keyboard and joystick and mouse towards the touch screen (even though I still have my doubts with respect to touch screen in front of a terminal…).

A while ago, the CERN touch sensor was highlighted in media (maybe due to a 30-year anniversary). However, dependent on the definition of a touch screen and touch buttons, etc., the common opinion is however that the first touch screen was suggested (and implemented) by E.A. Johnson in the UK. It used a capacitive technology and enabled touching on different parts of the screen.

User interfaces, the Pantomation, 1977

Speaking of user interfaces. This is a rather cool one: the Pantomation was a product out of research done at the SUNY in the latter half of the 1970s. With the aid of a camera and a computer they used indicators (of distinct color) that you kept in your palm, or strapped on to your feet, or where ever. The computer could then track the objects and on the screen overlay with artifical, CGI objects – in real-time. This predates the xBox and play stations by quite a few years.

Apparently it was first used for the music arena and musicians. I bet that Kraftwerk would have been interested in this one.

The movie tells the whole story quite well and I guess it is just a question of time before we see this in our phones too.

Pay with your phone, 1997

With swish, mobile banking, and what have you in your phone today, we are now starting to effectively replace cash and credit cards and instead do payments on-line. But when did we do our first mobile banking or payments?

These services were first offered in Finland in vending machines (Note, it was Coca-Cola, not alcohol!). The payment was done through SMS. In some sense impressive, since the first commercial SMS was sent in 1992. Interestingly, as late as in 2011, this was still considered an innovation.

[Picture from Indiamart.]

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