How to perform first attempts at learning about electronics

My favorite single source for electronics learning- everything from basic resistor, capacitor, transistor circuits to advanced theory that explains some complex portions of cell phone and cable modem communications.

http://www.amazon.com/ARRL-Handbook-Radio-Communictions-Communications/dp/1625950195

Also back in day, Jon Titus, Christopher Titus and Dave Larson published an introductory book on interfacing to the Apple II.

http://www.applelogic.org/files/APPLEINTERFACING.pdf

When I developed the Superproto board I had some ideas on coming out with a revised version of that book that utilized the Superproto as the hardware platform. There hasn't been that much love for the Superproto, so I dropped the idea. I did create a wiki with an introductory project, though.

http://willegal.net/superproto/index.php?title=Main_Page

Check out the blinking LED experiment. If you can figure out how a LED is controlled, you are half way there. Most of the rest of digital electronics theory is variations on the theme of switching a circuit on and off.

regards,
Mike Willegal

Also the old MOS MCS6500 reference manuals are outstanding, something rarely seen in publications by chips makers.

http://arlet.home.xs4all.nl/mcs6500_family_hardware_manual.pdf
http://archive.6502.org/books/mcs6500_family_programming_manual.pdf

-mike

My favorite single source for electronics learning- everything from basic resistor, capacitor, transistor circuits to advanced theory that explains some complex portions of cell phone and cable modem communications.

http://www.amazon.com/ARRL-Handbook-Radio-Communictions-Communications/dp/1625950195

Also back in day, Jon Titus, Christopher Titus and Dave Larson published an introductory book on interfacing to the Apple II.

http://www.applelogic.org/files/APPLEINTERFACING.pdf

When I developed the Superproto board I had some ideas on coming out with a revised version of that book that utilized the Superproto as the hardware platform. There hasn't been that much love for the Superproto, so I dropped the idea. I did create a wiki with an introductory project, though.

http://willegal.net/superproto/index.php?title=Main_Page

Check out the blinking LED experiment. If you can figure out how a LED is controlled, you are half way there. Most of the rest of digital electronics theory is variations on the theme of switching a circuit on and off.

regards,
Mike Willegal

That book on Amazon... Are you sure that it talks about basic components? It seems to be a book on Ham radio and radio in general.

Please Bare with Me as I try to determine what you understand about Electronics and What you Don't..

First, a Little Chemistry... Back in the Day, ( Circa 1987 ), my College Classes talked about Conventional Theory and Electron Theory.

Conventional Theory says that Current, Flows from the Positive Source, to the Negative Source...

Electron Theory says that Because in a Conductive Material, like a Copper Wire, the Electrons Flow from One Atom of Copper to Another, thus, Electrons ( e.g. The Current ) flow from the Negative Source to the Positive Source...

As much as I like to be Positive... Electron Theory makes more sense... So Negative I will be... I would guess they don't teach Conventional Theory any more....

And I am bound to make some mistakes here, so Please Correct me if I Mess Up...

This little SparkFun Tutorial, What is Electricity, which has a good description of Electricity and How its Generated.

It's all about understanding how transistors work, and knowing the difference between NPN and PNP.

An NPN transistor has a collector and an emitter which is doped negative, while the base is doped positive. A PNP transistor has a collector and an emitter which is doped positive, while the base is doped negative. That's the difference primarily.

And that Sums Up the Physics Side of NPN verses PNP Transistors.. But What Does That Mean to an Electronics Technician or Electrical Engineer??

Current ( or Electrons ) Flow from the Emitter to the Collector, ( for an NPN Transistor ) or Holes for Current Flows from the Emitter to the Collector, ( for an PNP Transistor ) Thus you need to know Which Type of Transistor you have, so you know Which Side of it to connect to the Current Source.

Also the Base is Controlled Differently between NPN and PNP... The NPN Transistor is Controlled with the Presence a Voltage from your Power Source, say 5 Volts DC, where as the PNP is Controlled with the Presence of the Ground from your Power Source.

Here is the SparkFun Tutorial on Transistors.

Transistors are like a Control Valve, "with no moving parts" ( e.g. Solid State ). A tiny bit of Voltage and Amperage can Control a Larger Amount of Voltage and Large Amount of Amperage..

Sometime they are use in a Simple ON or OFF State.. That's Binary..

Sometime they are use with Varying Amounts of a tiny Current, to Control Large Amounts of Current. This would be for Amplification of a Signal.

What confuses me is the method of which a "control valve" works. What exactly is the flow of amps or volts coming in the transistor to which parts of it that controls the flow?

Amps is the AMOUNT of Electrons, and Volts is How Hard they are being Pushed, ( think Pressure ).

With an NPN Transistor, The Negative Side of the Power Source is Connected to the Emitter, but the Electronics Can Not "push through" to the Collector Side, Unless the Positive Side of the Power Source, Connected to the Base, is High Enough. This is True, until the Voltage of the Power Source, Exceeds the Transistors Capabilities, in which case, ALL Bets are OFF..

Look at the Section, Symbols, Pins and Construction.

And binary what? This is voltage and current, right? How is the voltage being converted into computer information?

Binary means that the Transistor is Either ON or OFF, never Partially ON, or Partially OFF... A basic Dynamic, Random Access Memory Cell, ( DRAM ) is made of One Transistor and One Capacitor. Current DRAM is more Complicated, but performs the Same Function...

Your CPU, by Turning ON or OFF the Different Address Lines, can Select an Exact Bit of DRAM Memory, and then with the Data Lines, Write a One or a Zero, cause the Transistor to Charge or DisCharge the Capacitor. Later, the CPU can go back to that Same Exact Bit of DRAM Memory and Read the Charge of the Capacitor.. No Charge is Zero, a Charge is One.

Transistors are not a beginning topic... Volts, Amperes and Ohms are the Start

I am aware of what these things are to a certain extent. But it does not help much.

So read SparkFun's, Voltage, Current, Resistance, and Ohm's Law and Resistors. There should be a page on Capacitors and Inductors somewhere..

Find a copy of Forest M. Mims III's "Getting Started in Electronics". I bought mine at Radio-Shack a few years ago...

Ask Questions here too...

MarkO

I have that book. But it won't give me the, "AHA!" that I need to go off in my brain which tells me that I understand something. There is something missing here and I don't know what it is.

Speedy, I am sorry for not yet using your new thread but I intend to.

MarkO, what is confusing me is that if a transistor is a kind of valve, then what is the base for? A transistor has been doped with positive and negative material, so there has to be parts of it that somehow repel or allow voltage and current to flow through what? There are supposed to be the flow of positive and negative voltage and current through the transistor but what do these doped parts of the transistor do? Shouldn't they stop the flow all together like hooking up a battery the wrong way which discharges them both?

The ONLY valve that makes sense to me is the diode.

The diode. Now THERE is a device which acts like a valve. It allows power to go in one direction but not the other.

When Comparing Electricity to Water, the Diode is like a "Check Valve", it Only lets Water ( electricity ) flow One Direction...

The Transistor is more Like a Fire hydrant.. With a .5 Meter Spanner ( 18" wrench ), and your Arm, you can Open a Valve that lets Water Flow, anything from a Couple Hundred Gallon ( 750 Liters or so ) per minute, to One Thousand Plus Gallons ( 3800 Liters or More ) per minute.

Did you know that when Closing Down a Fire hydrant, the Valve must be Closed very slowly.. Because when it's OPEN, there is lots of Water Moving towards that Fire hydrant, and very quickly.. If the Valve is closed Fast, the Water in Motion, has to go some where, so it finds the Weakest Points in the System, that would be usually in your House, at the Faucets or Shut Off Valves under the Sinks or by your Toilet ( Water Closet ) I understand that it is Not a Pretty Picture. Even closing it Slowly, there is a Pounding, a Water Hammer while turning it off..

( This information I learned while being a Volunteer Fireman... When you live so far from the Station, You start out at the Bottom, as the Hydrant Man on the Second Out Truck... )

MarkO

yes, the ARRL handbook contains chapters on

Electrical Fundamentals
Analog Basics
Digital Basics

MarkO, Thanks for your reply.

Now as for Conventional Theory vs. Electron Theory: I heard somewhere that in the early days of electronics, they had one theory which turned out to be wrong and people are still being taught this way even though we know that technically it's wrong.

While I take the time to look at your links, I will answer a few of your questions.

In high school, I was taught several concepts about electronics.

Resistor = reduces power/resists electric power

Capacitor = A device that charges up and discharges electricity very quickly.

Diode = A device that permits electricity to flow in one direction and not the other.

Attenuate = something that reduces power.

Transducer = a device which changes one form of energy to another.

Sine Wave = a voltage or current, changing amplitude, direction, and polarity periodically.

Bridge Rectifier Circuit = A circuit that changes AC power to DC power.

DC = Direct Current.

AC = Alternating current.

AM = amplitude modulation.

FM = Frequency Modulation.

Ohm's Law = E=I*R R=E/I I=E/R <-- I think.. E is voltage, I = current and R is resistance.

Oh, and when I try to learn about how a transistor works and I hear the word, "holes" I go completely mad. At that point, I get ready to give up, since I know where the tutorial is going. I just can't understand that.

www.falstad.com/circuit/

It's rather simplistic but maybe it will work for you.

www.falstad.com/circuit/

It's rather simplistic but maybe it will work for you.

This is exactly like algebra. You get one example of something and you learn it, only to find that when the numbers change, the lesson learned seems useless and you can't find an answer to your problem. You then say to yourself, "what the heck does THAT mean?"

Thank you for your help, but that website didn't help me 100% either. It showed me how the power flows but it did not show me the connections.

Then I went to this website:

http://www.build-electronic-circuits.com/how-transistors-work/

And the "AHA!" Finally went off in my brain.

Here are the problems I had:

1). Amplification. The transistor does not actually amplify anything, it only CONTROLS the current that flows from the collector to the emitter. Changes in voltage connected to the base and the emitter will ALLOW different amounts of power to flow. The "changes in voltage" that I mentioned is like a water faucet. Change the position of the faucet, and the water flows at different rates.

2). The base. The transistor turns on when at least 0.7 volts is hooked up to the transistor in this way : The positive of the 0.7 volts is connected to the base, and the negative is connected to the emitter.

3). Connections: Ground is connected to the emitter, the positive is connected to the collector.

So then. I need you guys to verify that what I have said is correct. Maybe that website is wrong or my words are not 100%.

See, why is everyone else saying that the power flows from the emitter to the collector?

The only answer I have come up with is what MarkO said.

Conventional Theory says that Current, Flows from the Positive Source, to the Negative Source...

Electron Theory says that Because in a Conductive Material, like a Copper Wire, the Electrons Flow from One Atom of Copper to Another, thus, Electrons ( e.g. The Current ) flow from the Negative Source to the Positive Source...

As much as I like to be Positive... Electron Theory makes more sense... So Negative I will be... I would guess they don't teach Conventional Theory any more....

Here is another thing I found that may explain this conundrum.

MORE ABOUT THE DIRECTION OF CURRENT FLOW

An electrical current is the movement of electrons through a conductor or semiconductor. Since electrons move from a negatively charged to a positively charged region, why does the arrowhead in a diode symbol point in the opposite direction? There are two reasons:

1. Beginning with Benjamin Franklin, it was traditionally assumed electricity flows from a positively charged to a negatively charged region. The discovery of the electron corrected that. (but most electrical circuit diagrams today still follow the old tradition in which the positive power supply connection is placed above the negative connection as if gravity somehow influences the flow of a current.)

2. In a semiconductor, as shown on page 44, holes flow in the direction opposite that of electron flow. It's therefore common to refer to positive current flow in semiconductors.

For accuracy, in this book "current flow" refers to electron flow. But we're stuck with symbols that indicate hole flow.

If I did something wrong, can you guys tell me where I did wrong?

The transistor is a fairly complex device, with a number of different characteristics, some of which may be more or less important depending upon the circuit it's in. Transistors typically are used as amplifiers or switches.

When used as an amplifier, the NPN transitor controls collector-emitter current depending upon base-emitter current. The critical specification listed in data sheets is hFE, which will vary some, depending upon both current and voltage. A typical value for hFE might be 100. In other words, 1 milliamp of current, could be amplified in a transistor with a hFE specification of 100 to 100 milliamps. An example where this is used, is in my model rocket launch circuit (http://www.willegal.net/blog/?p=5694). Normally if you connect a LED directly between power and ground, it will conduct excessive current and fail due to overheating. However, in this case, the transistor is amplifying the base-emitter current by about 250, which is enough to light the LED, but is not enough current to burn it out. Note that in this case, there is no need for the current limiting resistor that is normally associated with LED circuits.

When used as a switch, the circuit is set up to go from off state to maximum amplification (fully saturated), usually as quickly as possible. Change the 100K ohm resistor on the base of the transistor in the model rocket circuit to a 1K ohm resistor and it would be set up for switching, instead of amplification. For a 10 volt power source, this, would generate 10 milliamps of current from base-emitter. This would require a current limiting resistor on the LED input or output to prevent either the transistor or LED from being burned out. This is because the transistor would be operated in saturated mode, and could essentially conduct at least 100 times the 10 milliamps of current. This would be at least 1 AMP, which is more than either device can support without overheating and failing.

regards,
Mike Willegal

The transistor is a fairly complex device, with a number of different characteristics, some of which may be more or less important depending upon the circuit it's in. Transistors typically are used as amplifiers or switches.

When used as an amplifier, the NPN transitor controls collector-emitter current depending upon base-emitter current. The critical specification listed in data sheets is hFE, which will vary some, depending upon both current and voltage. A typical value for hFE might be 100. In other words, 1 milliamp of current, could be amplified in a transistor with a hFE specification of 100 to 100 milliamps. An example where this is used, is in my model rocket launch circuit (http://www.willegal.net/blog/?p=5694). Normally if you connect a LED directly between power and ground, it will conduct excessive current and fail due to overheating. However, in this case, the transistor is amplifying the base-emitter current by about 250, which is enough to light the LED, but is not enough current to burn it out. Note that in this case, there is no need for the current limiting resistor that is normally associated with LED circuits.

When used as a switch, the circuit is set up to go from off state to maximum amplification (fully saturated), usually as quickly as possible. Change the 100K ohm resistor on the base of the transistor in the model rocket circuit to a 1K ohm resistor and it would be set up for switching, instead of amplification. For a 10 volt power source, this, would generate 10 milliamps of current from base-emitter. This would require a current limiting resistor on the LED input or output to prevent either the transistor or LED from being burned out. This is because the transistor would be operated in saturated mode, and could essentially conduct at least 100 times the 10 milliamps of current. This would be at least 1 AMP, which is more than either device can support without overheating and failing.

regards,
Mike Willegal

Thank you, I almost understand completely what you said.

I know that what you said has something to do with forward and reverse bias.

Can you explain this to me in a simple way?

ITT uses the best book available: http://www.amazon.com/Electronic-Principles-Simulation-Albert-Malvino/dp/0073222771
I've trained over 50 techs with it, and still use the teacher's edition today.
Not too much, just right for teaching/training.
AFTER you get the basics, there are MANY more for college level courses, EE degrees, etc.
Michael Kinnaird
I.E.E.E. ISCET, GeekSquad trainer in Birmingham AL

ITT uses the best book available: http://www.amazon.com/Electronic-Principles-Simulation-Albert-Malvino/dp/0073222771
I've trained over 50 techs with it, and still use the teacher's edition today.
Not too much, just right for teaching/training.
AFTER you get the basics, there are MANY more for college level courses, EE degrees, etc.
Michael Kinnaird
I.E.E.E. ISCET, GeekSquad trainer in Birmingham AL

The reviews on that are absolutely terrible. The reviewers say that the books arrive used, damaged and lastly, the CD that comes with it is useless. It actually does not come with the "simulation CD" as advertised.

Theory aside, from a practical point of view, forward and reverse bias are mostly diode concerns - do some reading up on diodes. I recommend experimenting with some basic circuits on a breadboard. Light a led, trigger a relay, that sort of thing.

regards,
Mike Willegal

I found this video which really puts things into the proper perspective:

https://www.youtube.com/watch?v=7ukDKVHnac4