Electricity
Ok, now we have magnets and can make them of any shape of polarity we need. We also know how to make copper wire. Now we can make a generator.
There are two basic types of generators, DC and AC. DC stands for direct current and AC for alternating current.
Generators
To understand what DC (Direct Current) and AC (Alternating Current) represent, we first need to know that electricity is generated when a wire is present within a magnetic field, and it is only generated if a change occurs. This implies that if you place a wire within a magnetic field, it will not produce electricity by itself. Either the wire or the field needs to move or change to produce any electrical output. Additionally, it's crucial to understand that electricity can travel along the wire in both directions. The direction it travels depends on the position of the magnet.
Imagine we have a flat coil that we rotate between two magnetic poles. The highest concentration of magnetic flux is in the middle, and as the wire approaches it during rotation, the voltage in the wire increases. As it moves away from the flux, the voltage decreases. This is Direct Current, but it's pulsating, unlike the battery-powered current, which remains constant.
The fundamental difference in how AC (Alternating Current) and DC (Direct Current) generators operate lies in their wiring configurations. Illustrated below and on the side are two methods for wiring a generator. One aspect to consider is the role of the brushes. The concept of brushless motors and generators is a relatively recent development in our history. Brushes can wear out and lose contact with the wire, so a clever solution was proposed to circumvent this issue: instead of moving the wire, move the magnets, thereby eliminating the need for brushes. This is a simple example of the kind of thinking required when reading this book, as it won't provide all the answers, but it will guide you in the right direction. How you utilize or further develop this knowledge is entirely up to you.
One additional caveat to note is that brushed generators and motors, when used with high voltage, can produce sparks between differently charged plates, which decreases both efficiency and lifespan.
We can increase the efficiency of the DC generator by introducing more coils which in turn has an effect to reduce the ups and downs of voltage produced by the generator bringing it more to a flat line.
Transformer
A transformer is a device that modifies alternating current (AC). It can increase or decrease voltage and amperage. It is a straightforward device with no moving parts. The only aspect that could be considered "moving" is the alternating electric current itself. Direct current (DC) cannot operate this device because DC generates a stable magnetic flux, while AC generates an alternating magnetic flux.
If you've read the earlier section about galvanometers, you should understand that electric current or voltage is generated by the movement of a magnetic field in close proximity to a conductor, and vice versa. In a transformer, the magnetic field moves without any mechanical parts by using alternating current. By alternating the current, the magnetic field generated by such voltage changes behaves as though it were moving, producing the same effect.
The transformer consists of an iron donut and two coils around it. An important note is that wrapping them in nonconductive mediums like silk, cotton or some varnish insulates wires. The alternating magnetic flux generated by the first coil that has a certain number of windings of wire travels within an iron donut that has higher permeability than air. This acts, as would a magnet that moves within the second coil. The alternating magnetic flux is inducing a new voltage within the second coil whose voltage and current are different if the number of winding to the first coil is different.
Now, an explanation of why this device is so important. Let’s say you want to transfer electrical energy across the wire for a certain distance. As the wire has resistance it will heat up and power is lost in the heating of the wire due to its resistance being proportional to the square of the amperage. So, it saves a lot of energy to transmit the electrical power from the power station to the city at very high voltages so that the amperage is only modest. Modest in terms of modern power lines is deceptive it is still more than enough to kill you.
On the other hand, if you increase amperage and reduce voltage you can use that heat energy for welding metal.
Welding
There are many ways to weld metals together. The first one described is maybe the easiest if you have enough electrical power. If you have good generators or batteries you can weld metals with ease.
Let’s say you have an alternating current generator that can produce some noticeable amounts of power. What you would need is a transformer, a closed donut made of iron where a lot of wire is wrapped at one end and connected to the generator while the other end of the doughnut is wrapped in a couple of windings of thick wire and is not closed. This gap is where the magic happens. To start make sure everything is insulated and don’t touch the wires with bare hands. Take the two wires that exit the transformer on the secondary side and fix them to a piece of wood. Wood is nonconductive so you should be able to operate the wooden handles. Press one to the metal and slowly start to bring the other close to it. An arc will form that will be of such a high temperature that metal will start to melt at that spot. Uptime welders use a second piece of metal that is held with one end of the welder and that piece acts as a conductor and as welding metal. This difference in the number of windings is crucial as it increases the amperage and reduces voltage.
The second way is maybe even easier if you have an ample supply of powerful batteries. Just connect the batteries in series and the rest is the same.
Arc furnace
An Arc furnace is an extension of the welding process. The heat generated that is used for welding if modified slightly can be used to meld almost anything. With temperatures of up and above 1.800C, they have used uptime in the production of iron, aluminum, and almost anything that needs melting.
The difference from welding is the way it’s used welding is handheld and used to combine materials by melting the joining points. Arc furnace uses graphite electrodes that are introduced in the kiln. Kiln functions as an opposite electrode in arc welding.
Capacitor
A capacitor is a storage device of electrical charge. It can be constructed in many ways but the first one constructed is called the Leyden jar. Nevertheless, capacitors use the same principle. For the construction of a capacitor, one would need a conductor and an insulator.
Capacitors can occur naturally. Any two wires close and parallel to each other can have differences in electric potential. Such capacitors can affect the electric circuit but their effect, for now, we can disregard, as it is negligible.
The use of capacitors is hard to understand but easy to explain.
Capacitors are also used as filters. They will not allow direct current to pass but will allow the passage of alternating current. There is no passage of electricity but of charge, as there’s an insulator. Again, the property of alternating current to vibrate is the culprit to its success. While direct current will build up charge in the capacitor only alternating current will actually look like it is passing through.
Also, they will act as a frequency filter.
Capacitors can be also made as variable capacitors. It is made from a two-interlocked system of plates. One set of plates is fixed while the other is able to rotate between them. All of this has to be made so that they never touch but are as close to one another as possible. Air is the dielectric. As the position of the rotor is changed, the capacitance value is likewise changed. This type of capacitor is used for tuning most radio receivers.