The History of Electronics

“The Building Blocks of Science”

With all Science it is the same as it ever was. Some things are newly discovered and some things have been disproved . It goes without saying that if something “is” today than it was also “so” yesterday as far as science is concerned. The Earth was never flat though back in the day you could be hung or worse for saying that the earth was round. It’s amazing how science has evolved over the years. I’d say for the most part science is about building blocks. Not wooden toy blocks but about connecting the dots so to speak where the different basic science principles and devices are grouped together to enhance and sometimes to create a different more advanced scientific device.

For example: These are a few that come to mind;
A typical car, motor cycle, air plane, bicycle, washer and dryer, refrigerator, lawn mower, computer, …well the list is virtually endless. All of these things use multiple building blocks of science to be what they have become in today’s world.

The human body is also a lot of science rolled up into one amazing organism that makes up mankind as we know it. Lets not go there now because this is not about religion. Lets Stay focused.

I’d really like to breakdown a few things for you so you understand where I’m coming from and where I’m going with all of this. Some things are very interesting in the field of electronics and the building blocks in electronics are the back bone of most of your most popular gadgets.

Lets start with devices that work or operate on DC current . That is short for “Direct Current”. Direct current is the flow of electrons thru a conductor such as for example “wire” and flows in one direction from negative to positive . Your cars electrical system is DC even though it has an alternator that initially produces AC or “Alternating Current”. The AC is quickly changed to DC by a Rectifier circuit and a voltage regulator keeps the voltage within a set voltage range.. These devices are typically built into the alternator so the voltage leaving a modern day car alternator is DC current. If you know anything about old cars you know that the voltage regulator was a stand alone device back then.

The reason cars use DC is simplicity. The negative side (at least on modern cars) is always grounded or bonded to the car. That means that for any device (lights, horn, radio, whatever, it can obtain the negative side of the circuit by just connecting it to the metal chassis of the car. That saves a lot of wire and wiring. The positive side is actually protected by an inline fuse or the cars fuse box. Some devices are traders and don’t care if the power source is AC or DC such as incandescent light bulbs, but for the most part most things operate using DC power. Hats off to Thomas Edison for his discovery of DC.

The fact is that most of your appliances operate using some or all DC and therefore must convert the AC power from your household receptacle to DC before it can be used. This is done by using something called a rectifier circuit that is made up of either two or four diodes. AKA (Bridge rectifier). A capacitor is usually used with this circuit to smooth out any AC ripples in the newly transformed DC power.

DC circuits consist of several building Blocks compiled together to perform a specific function. These are some of the key components used today and a brief description of what they can do:

Resistor – resistors come in many wattage and resistance ratings. It’s primary function is to provide a predictable resistance to current flow in an electrical circuit.

Capacitor- a device typically measured in “uf” or microfarads and is capable of storing and releasing a charge. It does not allow DC current to pass thru it but AC current can (sort of). It is also used as a filter in some instances. I’ll explain this later in my own theory.

Transistor (NPN and PNP) an electrical type valve where either a positive voltage applied to a NPN opens the valve or allows current to flow thru it. A PNP opens the valve when a negative voltage is applied.

Transformer (Step up, step down, isolation, multi tap, )
Coil – sometimes called a choke or inductor can be used in LC circuits to tune into a given frequency. Used in radio and other similar receiver and transmitter circuits. Other types of coils are used in conjunction with magnetism to cause an induced voltage and that is the basis of creating alternating current using alternators and generators.

Electron Tube (Typically used in older electronics and Hi Fi Amplifiers.It also acts as an electrical valve)

Switch – a switch can be used in an AC or DC circuit to effectively turn off a device connected in series with it. (N/O -normally open, NC – normally closed, momentary, latching, toggle, and more.

Fuse – A fuse is a device that is configured to be in series with a circuit and to blow or burn out if the amperage rating for that circuit is exceeded. They are necessary and are used to prevent fires and meltdown of components.

Thermal Breaker – Like a fuse a thermal breaker will open the circuit when the amperage is exceeded but after the breaker has cooled down the circuit closes again. Many power tools and some appliances use these. Most motors have thermal breakers built in to prevent the coils from getting too hot which would cause the coil coating from burning off and causing a short circuit in the motor windings. Once that has happened it’s a gone-er.

Speaker – A speaker simply reproduces sound by way of voltage and Frequency modulation.
Incidently the best way to check a speaker to see if it has had a coil meltdown is to just check the resistance with an ohm meter (preferably digital but an analog meter will also do). If the speaker is an 8 ohm speaker and your getting anything less than that as a reading such as 1-7 ohms you can be sure that someone has melted down that speaker coil. An open circuit across the terminals means the coil is toast. The closer it reads to eight ohms the better it is going to sound. (Remember I’m speaking of an 8-ohm speaker). Some speakers are designed to be four or even 16 ohm speakers. You’d probably think that a thermal breaker would be perfect to prevent this kind of melt down. I wouldn’t try it unless you have a load resistor in parallel with it. Many amplifiers have a nasty flaw that causes the power transistor in the power amp to fry if the speaker circuit opens up.

Tunable circuits – (LC and RC) respectively Inductive Capacitance- (LC) and Resistance capacitance circuits are both tunable circuits that can be tuned in to a radio frequency by changing the value of one of the components in the circuit.

Crystal – Crystals were used commonly in radios, scanners and CB’s and made to resonate or vibrate at a specific frequency. Today electronic tunable circuits have pretty much taken over and taken the place of the mighty crystal.

Relay – A relay consists of an electromagnet and contact switches that either open or close when the coil is energized. Control relays are used to enable low voltage circuits to control the switching on and off of high voltage circuits.

Most of the things I have mentioned are the basis for modern electronics. Silicon has now changed the way things are made. A Silicon chip is like a mini city or town of transistors.
I still think aliens came up with it. But that’s just my thoughts..

When you start combining these small components into real active circuits and then you start combining these circuits together then you start getting things like we see today. Modern televisions, radios, CD players, and yes lets not forget our new modern day friend the computer.

If you’d like to read more about the building blocks of Science and the development of modern day computers please read the article “Science Today” a continuation of this article that lays it out in plain english. Thanks for taking the time to expand your mind.