POWER is like the volume of water that is flowing from the hose, given a specific pressure and diameter. Now, let’s keep using the hose analogy to dive into the murkier waters of circuits (pun intended, sorry). The ability to move electricity over long distances is the main reason AC beat out DC a century ago. The electricity can travel farther with fewer losses because the resistance (sand) doesn’t impede the electricity (water) when the current is lower (smaller diameter hose). This is exactly what transformers do for overhead powerlines.

The water volume (power) remains the same but the pressure (voltage) increases as the diameter (current) decreases.

TRANSFORMERS are like holding your thumb partially over the end of the hose to get the water to spray farther. They include amp-hours and kilowatt hours. There are many metrics used for the capacity of batteries and not all are immediately logical. It is probably best to look first at the tutorials and then at the blog, if you are hungry for more information.BATTERIES can be thought of as water pumps that circulate water through a hose that travels in a closed loop back to the battery. In some posts he explains questions that readers have emailed to him. Storr is also writing a Blog that contains some additional topics, some of them a bit more advanced than those that are covered in the tutorials. By the way, the allaboutcircuits forum that is associated with Kuphaldt’s book, is a very good place to ask if you have questions about any topic in the tutorials. But if the pace of the tutorials is too fast for you, try Lessons In Electric Circuits (allaboutcircuits) by Kuphaldt - it will take more time to work through them, but they might be easier for the absolute beginner. If you work through the tutorials you will quickly gain a good basic knowledge of electronics. The AC-Theory tutorial contains a good explanation of the necessary trigonometry, and also of complex numbers (for a more in-depth treatment of this topic, please take a look at the resources on my Complex Numbers page). But even without this you can understand most of the tutorial. For a few pages of the tutorial, the knowledge of a bit of mathematics would be useful, for example in the DC-Theory tutorial the advanced methods of circuit analysis require linear algebra. The tutorials do not assume prior electronics knowledge of the reader. On the homepage the tutorials are listed in alphabetical order, but going through them in that order does not make much sense. The tutorials are independent of each other, but if you are new to electronics you might find it useful to look at them in the order in which I have listed them in the last paragraph. Each tutorial consists of about 5 to 15 consecutive pages which should be read one after another. Digital topics are also covered, ranging from the Binary System, Boolean Algebra, Logic Gates to Combination Logic, Sequential Logic and Counters. Wayne Storr has created a very good set of tutorials, ranging from DC- and AC-Theory over the basic devices Resistor, Capacitor, Inductor and Diode to Transistors and Operational Amplifiers and to circuits like Amplifiers, Oscillators and Waveform Generators and Filters.

The tutorials are listed in alphabetical order, but if you are new to electronics, I would recommend to start with DC Theory.

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