Index | A | A.138.1 # Circuits and Reality

I found this schematic in a book and pixelated it. We see a push button in the lower left corner, then comes the 12V DC + connector which leads to the relay. From the minus connector a 680 Ohm resistor goes to two LED's, which also lead to the relay. But now I have a completely different relay which I had examined. Does the circuit symbol look the same? Not exactly. The relay is a HF3FD subminature high power relay. Its label is different. I have pixelated everything so that it is as accurate as possible for the presentation in the book. It is also about showing differences later on.

How can the circuit symbols of electrical engineering introduce us like a language of our own. So when an electrical engineer reads a circuit diagram, he really does it. Through his education as an electrical engineer he can read and translate this language. There are even different dialects, for example the circuit A.138.3 symbols for country's are different. Some ones are a jagged line as you can see in the first schematic. In another country it is simply a rectangular box. Now there are two points of criticism.

• Circuit symbols are not uniformly organized worldwide
• Circuit symbols are too abstract as a teaching language

On the first point: I like to sort everything. To sort everything in a uniform way and to generalize a language so that it is understood by all electrical engineers on this planet. So you have to decide if you want to use the one or the another symbol for a resistor. How should a relay be represented? There are many points that need to be revised. And there we come to the second point. The language of the key sign should rather represent the reality.

Second. The language of electrical engineering is very technical. This makes it difficult for beginners to understand it. I am not talking about simplifying or changing the language, but besides the revised worldwide standard, there should be a second standard. The one for beginners, children and young people. Schematics that represent reality. An LED for example would look completely different. I think that people could be introduced to electrical engineering. It is important to make the initial contact as easy as possible and then to steepen the learning curve when you realize that there is interest in the language.

Let's look at the first point using a real example. There is a project that many people have already copied, because it is easy to convert and teaches a lot about electrical engineering. The Atari Punk Console A.176. I made a schematic with two 555 timers. To be able to concentrate better on the topic I left out all data.

You see the difference? Right! The resistors are drawn differently. As I described above, the resistors are drawn with a jagged line and the another ones as rectangular. This can be confusing for beginners, if they download circuit diagrams from the internet to build them at home. I can read both, but I prefer the European spelling of a schematic because I find straight angles aesthetic. As a counterargument you could say that this is just a personal taste, but that is not true. If electrical engineers from ESA and NASA want to work together they have to agree on a system. It can lead to fatal errors when technicians misunderstand something. In the same way, all technicians should use the metric system if they want to work with the rest of the world.

These were just a small example of what I wanted to show here. These circuit diagrams are drawn as neatly as possible, but there is also something here that bothers me a lot. Something very abstract is shown. Although the 555 timers have eight contacts that are used in the circuit, they are abstractly located on all sides. Wouldn't it be better if the NE555 timer IC was shown with eight pins, as it looks like in reality? Again, we would have to agree on a standard, because standards help different people to work well together in different projects. If you only have one cup size you can calculate in advance how many cups you have to buy to fill a kitchen cupboard. This is not nice if there is only one type of cup. But it is aesthetic and efficient.

Let's take a closer look at an NE555 timer A.138.1.1. What does it actually look like? We have a small black body with metal pins. The NE555 looks like a little spider. On the upper side a small semicircle is punched in. Sometimes a small dot is punched in the left side as well. This shows the user of the integrated circuit where the top is. The metal legs are numbered counter clockwise from top left to top right. Top left is the 1, then the 2 ... and top right is the 8th. We take a closer look at this in a pixel-art. Otherwise there is nothing more to discuss, because we are currently only looking at the appearance and not at the functions of the NE555.