# Things nobody told me when I started with electronics.

Since I started getting deeper into electronics I had to acquire information from many different sources. I knew about the basic theory but when it came to practical electronics I was quite lost at times. Looking back I would wish that someone would have told me the things below.

THEORY IN PRACTICE

Resistance
In theory books and data sheets the unit for resistance, Ohm is represented by the symbol Ω. In schematics however, you’ll find more often then not that values are written like 4R7 or 1k2. 4R7 means 4.7 Ω and 1k2 1.2 kΩ meaning 1200 Ω further R001 is 0.001 Ω which is 1 mΩ and 9M1 stands for 9.1 MΩ which is a bit short of 10 million Ohms.
In a circuit diagram R5 can stand for resistor No. 5 or for a 500 mΩ resistor (just mentioning).

Capacitance
I assume that the reader is familiar with the metric prefixes m, µ, n and p which are important when specifying capacitance in its unit Farad (F). While µF is often represented as uF the prefixes m, n and p are used as per definition. However, when it comes to the EIA codes, which are usually printed on smaller caps it gets a little bit confusing. There are two different scales for two different categories of caps. First to the easy part. The EIA code is a three figure number of which the last digit represents the amount of zeros before the comma or X in in the factor 10X if you will:
332 -> 33 x 102 which is 33 x 100 or 33 with two 0 in the end which is 3300.
474 -> 47 x 104 which is 44 x 1000 or 47 with four 0 in the end, which makes it 470000.
Following this logic, 100 is 10, 225 is 2200000 etc. There are the following exclusions from that rule. Even though we are still talking about caps you will also find values like 1R0, 2R2 or 4R7 which mean 1.0, 2.2 or 4.7 respectively. When printed on ceramic, film or tantalum capacitors the code translates in pF (332 means 3300 pF), for aluminum electrolytic and double layer caps to µF (331 means 330 µF).
Caps have also a voltage rating determining the maximum voltage for which the cap is intended to be used. This means a cap rated with 10 V should b able to handle 10 V or less. It is a rule of thumb to use a cap with a rating higher than the actual used voltage and leave some head room.

Current
If I hear someone using the word amperage my blood starts boiling. Even though electric potential difference (measured in volts) is called voltage – the flow of electric charge measured in ampere is called current and NOT amperage. Current!

EQUIPMENT AND PARTS

You can find a lot of and good information about how to set up an electronics lab. My opinions:

• If you solder a lot, buy a powerful adjustable station. I have an 80W Weller WD 1. It is that sort of an investment which will last for life. There are many good brands. Be sure, not to buy a fake. Oh, and a soldering irons don’t really need a USB connection.
• Looking back, I think it is smart to start with a sub 70€/80\$ multimeter instead a 200+ one. They are usually safe and do their job well. With the difference you can buy kick-ass pliers, cutters, screwdrivers etc. If you watch some video blogs of serious electronic professionals and hobbyists alike, you will notice that they have rather old and well-used hand tools. This is a sign for their quality.
I think one should not worry to much about that ultra accurate and precise Fluke, HP/Agilent/Keysight, Keithley or Gossen meter. If the time is right, it will come along on Ebay. It always did for me.
The point I want to make is a descent cheap meter will do for starters and then at a given time there are great second-hand options.
• I am a sucker for lab power supplies in all shapes and colours (well actually they are mostly white and gray). Sometimes I need accuracy, sometimes power, sometimes I like to quickly control them by hand via a potentiometer and sometimes I just want to charge a battery. With power supplies it is like with breadboards, the more – the merrier.
• There are many suppliers for IC’s. Some sell the real deal and some fakes. Unlike buying locally grown vegetables  from your local store, it is saver to stick to the big suppliers for electronic parts.

EDUCATION/LITERATURE

Again I can just talk from my experience. There are some extensive and profound books about electronics. Because they are written on quite a high level it is hard or impossible to read them front to back. If one wants to know more about, let’s say filter design it makes very much sense to read the according chapter. On the other hand there are books which are written for novices. Unfortunately some of them are also written by novices and contain plenty of mistakes. If something, while reading such a book, seems illogical check online if this is really true. I have lost countless hours to ponder over some “fact” from a book until I realised that it was plain wrong. recently I noticed, that some companies in and around the DIY maker scene are trying to make quick money while praising themselves to be educational and giving back to the community etc.

For me Arduino and especially it’s big community have been great. I learned vast amounts while building stuff with the help of the Arduino Forum and the Playground. If you get the chance to participate in an Arduino workshop, it might be well worth it.

I am sure you will find practical electronic projects you are interested in. For me it was building guitar effect pedals, synths and other noise makers as well as light and sound installations.

As an old man once said: I hear and I forget. I see and I remember. I do and I understand.