Basic Electronics

I wrote a course that I presented to college level students back in the 90's. It covers a basic understanding of how Integrated Circuits worked. Since then, the technology has improved significantly, but the basics remain the same. I'm going to try to break the course down into digestible segments for those who'd like to read it.

I plan to break it down into the following posts :

• Hole Movement and Current
• Voltage and Resistance
• Capacitors and Inductors
• Diode and Transistors
• Logic Gates
• Flip-Flops and Memory
• To Be Determined

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Hole Movement and Current

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Hole Movement

Atoms Contain:

• Neutrally charged Neutrons
• Positively charged Protons
• Negatively charged Electrons

Protons and Neutrons make up the Nucleus

The Electrons orbit around the Nucleus. They are being held by the attraction between positive and negative forces.

If you provide enough energy to the atom, you can free one of the electrons from its orbit, allowing it to float freely.
The space that the electron just left is referred to as a hole.

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Insulators, Conductors and Semiconductors

Insulators have valence bands that are full or almost full so it’s hard to free up their electrons

Conductors have valence bands with very few electrons. It takes very little energy to free these electrons from their orbit.

Elements that have half full valence bands are called semiconductors because they’re not quite insulators and they’re not quite conductors

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Hole Movement

With the electron gone, the atom has a void where the electron used to be. This void is called a hole

Any Atom with a hole has a net positive charge. So it’s going to to attract other floating electrons to fill that hole.

In conductive metals, electrons and holes are constantly trading places. Since this is truly random, the net movement of holes or electrons is zero.

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Current

If you apply an external source (such as a battery) the electrons will be forced to move in one direction more than another.

The electrons will move toward the positive terminal of the battery therefore, the holes will move toward the negative end of the battery.

This is current. It is usually represented by the letter I

The universally accepted direction of current flow is the direction in which the holes move.

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References

Electron Hole Movement
Electric Current

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Any comments/questions/recommendations?

Let me know if you found this useful/interesting. Do you have any recommendations for formatting?