Transistor Theory Good Resources?

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Ethan

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I've been trying to find a resource that explains transistor theory in such a way that dunces like me can understand. I have the usual AOE and I've looked in a few TAB books, but it makes me do that thing where I read the same sentence over and over and it still doesn't make a whole lot of sense. :roll:

Any recommendations?
 
Build a known good simple 1 transistor circuit like a guitar booster if you play guitar.

Then move the resistor values around to see on a scope and hear what happens.

Thing to try adjust the bias resistors to move the collect and emitter voltages.

Feed a signal to the circuit and look how the circuit clips with different operating points take note of the sound. This can adjust the harmonics the circuit generates under load.

Build a booster and a fuzz face type circuit if you play guitar very good to learn from.

Check Aron's stompbox page schematics one and the simple beginners project, the booster circuit as designed to be easy to build and also show the effect of a variable input R vs gain setting effect on the tone . If you look at my schematics you will sometime find a bias pot used to adjust the "sound" of the effect.

Then go back and reread the AOE sections then do more tests then read more books then do more tests

What do you want to learn about first Fets or Bjts? I have some good transistor books but some are from the mid 60' and are more in depth than AOE.

Don't worry about the Early effect and Base spreading Rbb stuff yet. Try to understand Re and how Hfe x say the emitter R helps set the input Z of a gain stage. Note in the the section about grounded emitter circuit how the temp can shift the operating point of the circuit and how the output waveform is distorted and the input Z changes with input level.

Or even ref a page of the AOE and ask a question I have the AOE in my house somewhere.

FWIW when I started playing with tube microphones I would often read then build a circuit and try different things then I would go back to a physics book or some of the more detailed tube books and try to understand what was going on.

Underheating was one of the thing that next to nothing is written about. then that helped me to learn about grid construction and it effects on tube microphones.

Doing tests and reading helps me, sometimes you just need to try/build something to get the understanding going
 
Doing tests and reading helps me, sometimes you just need to try/build something to get the understanding going

I couldn't agree more. I read all kinds of books. AOE, some books on transistor amps by Lindsey Hood. Opamp books by Jung. But now that i started trying out some simple designs myself everything seems to make much more sense.
Battery operated guitar stuff is ideal for this but i still need a good waveform generator.
 
[quote author="Gus"]Build a known good simple 1 transistor circuit like a guitar booster if you play guitar...[/quote]That was my first DIY back in '80. Sad part was, I couldn't afford an amp to plug it into. :sad:
 
Some relevent info, have fun reading! :thumb:

Designing Analog Chips

by Hans Camenzind

Content: 1. Devices Semiconductors, The Bipolar Transistor, The Integrated Circuit, Integrated NPN Transistors, The Case of the Lateral PNP Transistor, CMOS Transistors, The Substrate PNP Transistor, Diodes, Zener Diodes, Resistors, Capacitors, CMOS vs. Bipolar.

2. Simulation, DC Analysis, AC Analysis, Transient Analysis, Variations, Models, Diode Model, Bipolar Transistor Model, Model for the Lateral PNP Transistor, MOS Transistor Models, Resistor Models, Models for Capacitors.

3. Current Mirrors.

4. Differential Pairs.

5. Current Sources.

6. Time Out: Analog Measures, dB, RMS, Noise, Fourier Analysis, Distortion, Frequency Compensation.

7. Bandgap References.

8. Op Amps .

9. Comparators

10. Transimpedance Amplifiers

11. Timers and Oscillators .

12. Phase-Locked Loops .

13. Filters .

14. Power, Linear Regulators, Low Drop-Out Regulators, Switching Regulators, Linear Power Amplifiers, Switching Power Amplifiers.

15. A to D and D to A, The Delta-Sigma Converter.

16. Odds and Ends, Gilbert Cell, Multipliers, Peak Detectors, Rectifiers and Averaging Circuits, Thermometers, Zero-Crossing Detectors.

17. Layout.
 
> I have the usual AOE

90% un-read, right?

> and I've looked in a few TAB books

Ackkk! NO!!!!!! Do NOT read books printed by TAB. With few exceptions, they are hastily written by underpaid (sometimes underqualified) writers, then badly edited. One TAB book was so bad that I took it away from the kid who was asking me to make sense of its nonsense.

The Camenzind book is good but may start at a higher level than you are ready for.

I like Gus' advice. Build a 1-transistor amp, even a fuzz-box (which is sure to be "non-optimum" in the ideal sense), modify it, see what happens. Use a 9V battery so you can stick your fingers in it fearlessly: finger-buzz to speaker gives a gut-level sense of things that you don't get from DVMs.

KNOW OHM'S LAW!!! You have to be able to see voltage, resistance, and current the same way you see rock-chord notation and progressions. If I play two notes, you'll instantly hit a third note that fits; you have to "read" Ohm's Law just as smoothly. No calculator, no nomograph, no decimal places: 13V and 6Ω is 2A (close enough). So what is 11V and 6KΩ? Quick! Without thinking!
 
[quote author="PRR"]>So what is 11V and 6KΩ? Quick! Without thinking![/quote]
about 2mA (once again close enough :wink:) That's one thing I did take away from AOE, a faster close estimate can be more useful than exact calculations. I've been slowly getting better at solving basic problems, where before I didn't always SEEohms law in those problems. It still amazes me when some of you guys take a quick look at a schematic and spout off a dozen different interpretations of what's going on where. I wanna do that!!!:cool:

I'll go with Gus' advice and build a fuzzy and tinker.

DANK YA!
 
Ethan,

I get the impression that you're looking for (f)actual theory and design info, but just in case it helps here is my "BJT amplifer for dummies" explanation that I use with musicians...

"For our purposes, we can think of the basic transistor amplifer like this. A small device that has three terminals, an AC (audio) input, an AC output, and a DC input. It takes the small input signal (typically less than 1V) and shapes the much larger DC voltage into a proportionally equivalent copy, which is then travels onward as your amplified audio signal.

How does it do this? The DC input terminal of the device behaves like a variable resistor (the PN junction - is it conducting, insulating, or somewhere in between?) which changes value in correlation to changes in the AC input voltage. Think of it like a valve which is normally closed, but opens when the AC input terminal encounters a signal. If the signal gets bigger, the valve immediately opens to compensate. When the signal is smaller, the valve starts to close."

I preface this with a brief discussion of AC versus DC, saying that DC is 0Hz, just a flat line that doesn't move, whereas AC is moving fast enough that we can hear it when it vibrates a speaker. Voltage equates to loudness and the frequency at which it alternates is the pitch. Music is usually a wildly varying AC signal, and thus the DC bias voltage which has no sound is like a giant hunk of clay that the transistor can mold into any representational shape.

I know this is oversimplified and far from technically accurate but it helps when first trying to understand these concepts. If anyone has better analogies, I'm all ears.
 
That helps a lot Hoof. That just made me understand this chapter on transistors I've been reading a lot better.

Thanks!
 
The load line analysis graph and/or transfer curve really puts it into perspective. Not enough current, you're in cutoff and nothing passes. Too much current and you're in saturation (also known as clipping, hello square wave). Transistors that can jump between these on and off conditions very quickly are good for switching. This is what computer and digital designers want. For amplification, you want to keep it in the middle of the load line where response is most linear and then the rest is your headroom, so to speak, with increasing nonlinearity as you approach either end. This requires knowlege about your specific device, the basic equations for determining such conditions (or a scope and tons of experimenting instead :grin:), and external components to create a particular bias arrangement.

Once the concepts are down, start getting comfortable with the basic equations. Using a simple circuit like Gus suggested will help. It's much easier to learn this stuff when you have a desired application in mind. The theoretical examples in text books are so boring. Anyway, I should stop babbling and take my own advice. Quit while you're ahead, Jens!

P.S. My knowledge of transistors, which is very scattered, comes from a solid state course I took in college and a textbook called Electronic Devices and Circuit Theory, Eigth Edition by Robert L. Boylestad and Louis Nashelsky. Ironically, I didn't really start understanding or using any of this knowlege until after I quit studying EE and followed my own initiative.
 
may be someone has mentioned the link previously on the forum??

anyway, some more info here....

http://www.tpub.com/content/neets/14180/

main....

http://www.tpub.com/neets/index.htm
 
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