Dumbest Question Ever Asked

[grathan]

Transitors don't seem so magical after reading Electronics for Dummies. Didn't it say that they just amplify the signal?

[Baktown]

The Electra was my first ever build, and it almost made me give up entirely.  It turns out that the wiring diagram for the stompswitch was wrong, which I didn't know having justed started. 

I guess what I'm trying to learn is why all the different components are used in certain ways, how diverting signal to ground affects the sound, how a tone stack works, really basic stuff for most people.

Rick

[Baktown]

Did I mention that I possibly have ADHD, plus, I'm dyslexic, so I have a short attention span.  What was I saying?  I cant seem to remember....

[JKowalski]

I actually have one book that contradicts itself by saying that current flows from negative to positive, then in a later chapter says just the opposite.

If you look closely - that's not what it is trying to say.

There is a convention in electronics, when designing or reading electrical schematics, that current flows from the most positive voltage to the negative. This is the electricians view of what is going on.

However, if you look at it from a physics point of view, the current is actually flowing from negative to positive. This is because electricity is composed of electrons, which have a negative charge. So, there is an excess of electrons on the most negative voltage, and they flow to the positive (which lacks electrons) to even out the difference.

The reason we say it flows from + to - even though it really fundamentally doesn't, is because it does not affect circuit design, is it supposedly easier to work with, and someone just decided we should all do it that way.

Basically - don't worry about the physics view. Just act as though current flows from + to -.

There are only a few cases where you might need to understand the physics view, such as vaccum tubes - and even then, only so you can understand how they work, not so you can design with them.



I highly suggest reading the "Art of Electronics", and if that is too overwhelming, precursor reading it with some other slower or easier books. Go to your library and just grab a bunch of different books and try them out in turn until you find one you like. I found that every author has his own way of explaining the concepts, and there will be some that will just "click" with you.

I even have one book that spends like 50 pages just on the analogy of current as a flow of liquid! Maybe that's one you would like. XD To me, it wasnt that helpful, but like I said, maybe I just didnt "click" with his methods like you might.

[lazerphea]

Hello Baktown!
Hope to be of some help with this:

http://moosapotamus.net/IDEAS/stompboxology/GoingDiscrete.htm

At the link you can find an issue of this magazine called Stompboxology, that is fully dedicated to transistors, specifically to their use in stompoxes! I found it very useful, being myself a total noob!
Oh, and as someone said before, check this great thread, whose title is "what does that bit there do": http://www.diystompboxes.com/smfforum/index.php?topic=47572.0
Bye!

[rackham]

I've found this to be pretty handy in the past for transistor theory:

http://www.rason.org/Projects/bipolamp/bipolamp.htm

For simple RC filters this is useful:

http://www.sengpielaudio.com/calculator-RCpad.htm

[Baktown]

You guys are the greatest!  I printed a bunch of this stuff out last night and stayed up most of the night reading.  Still not 100% there, but getting closer.  I guess what's confusing to me is the CBE design of the transistor.  BTW, the Beavis Audio tech pages are great.  Highly recommended for people like me.

Rick J

[wampcat1]

nah, that's not the dumbest question ever asked... the dumbest question is 'which end of the soldering iron do I hold?'


bw

[grathan]

Speaking of dumb questions.... I was reading your book last night Brian, and on the first page it says almost all country music on the radio today (this is back when you were 31) has some influence by you. Very interesting , but was never elaborated.

[wampcat1]

Speaking of dumb questions.... I was reading your book last night Brian, and on the first page it says almost all country music on the radio today (this is back when you were 31) has some influence by you. Very interesting , but was never elaborated.

kinda, sorta. 

Brent Mason and Johnny Hiland who pretty much play on 90% of everything on country radio (they are session musicians) use alot of my pedals and modified pedals. For brent in particular, I built his entire rig with him.

BUT - honestly, those guys could play through a tin can with a rubber band and sound freaking amazing

bw

[tranceracer]

Not sure if this was mentioned earlier but this thread has some great insight to what parts do.

http://www.diystompboxes.com/smfforum/index.php?topic=47572.0

-bK

[Wales]

I have these old electronic engineering video tapes from 70's and as boring as they are that's how i came to understand transistors. I'll try and make as much sense as i can, but I am not good a writting what I am explaining.

a transistor has three parts as you know, pretend that inside the transistor there are three sections as well with small bridges between them. Lets also pretend that inside those compartments are boy and girl electrons (- boys and + girls). In the first area there is an equal numbers of girls and boys at the party. In the middle area there are mostly boys and only a few girls, sausage party. In the last section  it is also an even mix of boys and girls at the party.
Now when power is introduced +v to the first section it brings more girls to the party, but the girls that are there get upset that there are more women competing for the male electrons so they pick up ship and move over to the center where they know there are lots of boys.  Well the boys in the middle section are not use to the extra women around and get nervous so they move over to the next section which in turn throws that party off in ratio.
So I assume that know that one or more of the entrances to these party's are connected to ground or power by a resistor. now that resistor will only let a certain number of people out of the party (to ground or through the circut) or into the party (through the positive volts). And because these electrons are always trying to find a partner and the doorman (resistor) won't let them out you get variances or swings in electricity witch boost or alter the signal depending on which party room is letting people out and which is letting people in.
Obviously there are many different uses for transistors and types so the party rooms are aligned in different orders and have different capacities depending on the transistor type.

Kinda of a weird analogy but I hope it helps understand. I may be wrong in my thoughts here and anyone feel free to correct me that's just my understanding from the videos.

[Tony Forestiere]

I liked your analogy. The "sausage party" simile almost ruined another $9.95 RS keyboard (the beer through the nose thing).

[frank_p]

I don't understand: the boys have the hole in that theory , I tought it was the other way   

[Baktown]

nah, that's not the dumbest question ever asked... the dumbest question is 'which end of the soldering iron do I hold?'

Even dumber would be asking how to tell if the iron is hot enough by touching it with your finger...  LOL

On the sausage theory, the last time I checked (being a male for 50 plus years) I was under the impression that I was a + (outie), not a - (innie).  Of course, I am a product of the California and Oklahoma public school and university system!  LOL

Rick J

[grolschie]

Ok, I hope it's ok to bust in on this (I'm sorry if it's not), but letting current into the transistor, or out of the transistor to ground, how does this amplify signal path going through to the rest of the circuit? Could someone explain the path that the audio signal takes through the transistor boost circuit please? I like Dano's picture, but I still don't get this. Thank in advance.

[biggy boy]

I feel the same way baktown. I can follow the procedure but I don't really know how it really works. I'm grateful you asked this question because I've hit a similar roadblock in my pedal building trajectory. I don't wan to feel like I'm painting by numbers every time I build something.

I'm also grateful to those who replied with great possible resources that would help make it all make sense. Thanks for helping us attempt to take our build understanding to another level.

On an entirely different note, would baktown happen to be from Bakersfield, CA? I grew up nearby and it would be a grand intertubes coincidence.

Hi
I don't feel to bad using others designs. Stop and think, we are making these pedals. Were not buying them from a store, like the average person would.
I look at it as being a process, and one day I'll understand this stuff. It will eventually sink in, Little by little we learn.

I think we should be proud of our achievements.

[ollie]

Ok, I hope it's ok to bust in on this (I'm sorry if it's not), but letting current into the transistor, or out of the transistor to ground, how does this amplify signal path going through to the rest of the circuit? Could someone explain the path that the audio signal takes through the transistor boost circuit please? I like Dano's picture, but I still don't get this. Thank in advance.

I may be a little rusty as I finished my electornics class a year ago now, but a Transister amplifies current.

In a 'normal' circuit scenario the audio signal goes into the base of the tranny (B), the collector (C) is connected to 9v, and the emitter (E) is connected to ground with the output of the transistor coming from between C and 9v. A transistor is, in simple terms, a switch. When there is a signal (voltage greater than 0.7v in standard sili trannys) 9v is connected to ground and the output gets all the current that the supply can provide.

If I've said something wrong can one of the gurus point it out so I don't confuse anyone and do more damage than good hehe

Hope it's some help

[waky]

Ok, I hope it's ok to bust in on this (I'm sorry if it's not), but letting current into the transistor, or out of the transistor to ground, how does this amplify signal path going through to the rest of the circuit? Could someone explain the path that the audio signal takes through the transistor boost circuit please? I like Dano's picture, but I still don't get this. Thank in advance.

My way of viewing it (and please do correct me if im wrong, im barely starting with electronics) is:


When an ac signal is applied to the base it varies the voltage drop in the emitter resistor, and proportionally the collector resistor voltage will vary (if u dont understad why search for kirchoffs law online), of course for amplifying a signal your vcc must be alot greater than the original signal or it will clip, the output of the circuit if you think about it is of course between the transistor's colector and the  colector resistor.

a couple of things to consider:

- the base must be at least 0.7 volts more positive than the emiter (this allows forward conduction and is the reason trannies get biased at the base, because sometimes the ac signal isnt 0.7 volts more positive, for example at the negative swing).
-you also need a big emitter bypassing capacitor (if you phail to include it the voltage at the colector resistor wont vary, you include this to let the ac signal escape to ground and not messing the output)



again this is the way i see it... been reading around a little bit but i dont really know if im right!!

[Baktown]

OK, as a huge fan of drag racing, I'm going to try and understand this in terms of fuel being injected into an engine via injectors or a supercharger.

The AC signal from a guitar flows into the base of the transistor, correct?  The DC voltage from the 9V battery provides a significant boost to the pressure of the input signal by amplifying (or compressing) the flow of signal (fuel) from the input, correct?  So any unburned fuel (signal) then passes to the emitter (or exhaust).  This is where the analogy kind of falls apart as unburned fuel goes into the atmosphere.  The boosted signal from the base and collector then flows to the output capacitor which removes AC voltage, which then allows the amplified signal to pass to the output of the effect.

Am I sort of on the right track here?

Rick