reading schematics

[cream123]

I know it sounds stupid but it's something that I must learn, everyones got to learn sometime. How do read a schematic? I know that the signal goes from - to + but I don't understand it when it goes up and down as well as across. I don't know which way the signal goes when the wires that go up ad down attach to the wires that go across. I can read this :smack:

View attachment 5826

however when it gets one more step compicated like this, I'm totally stumped on which way the signal goes! :smack:

View attachment 5827

How do I tell which way the signal is going? Can a signal be split into 2 different parts and it all rejoins at the positive end or what?

I'm looking at the Thor schematic wondering what in the Jesus it says
View attachment 5828

I'm pretty sure I can get this down; any help will be appreciated.
-Marc

 

[Artie]

Re: reading schematics

Those pics aren't showing up. If you can get them to display, I can probably explain this to you fairly easily.

 

[greco]

Re: reading schematics

I await Artietoo's response as he is the expert.

That said, I'am trying to learn electronics as a hobby and I think of these circuits as multiple parallel/series (sometimes in combination, sometimes not) configurations.

The signal can be split into parts. Might help if you think of the wires as pipes with water in them and the battery/source as a water pump. The pressure, direction and flow/volume of water will vary in the pipes depending on the controls/inflences (i.e. components...resistors could be compared to taps partially shut off, etc.) Not a perfect analogy, but maybe helpful.

Sorry if this is analogy is comes across as insulting your electronics knowledge...it isn't intended that way bro.

NOW, I am curious to see what Artietoo writes.
Maybe I am "all wet" with what I wrote (pun is intended).

Dave

 

[cream123]

Re: reading schematics

Sorry if this is analogy is comes across as insulting your electronics knowledge...it isn't intended that way bro.

Far from it. It helps more than anything else I've found so far.

Arite...you seem to have problems with attached images. Anyway

Here's what i do understand. I hope so, I don't think it gets much simpler than this.

Here's what I don't quite understand

Here's something that makes me perspirate in fear every time I look at it :laugh2:

 

[MattPete]

Re: reading schematics

In Figure 1:

VR1 = variable resistor #1, i.e. a 10k potentiometer
R1 = resistor #1, 1k ohms.
NPN = an NPN transistor. C provides the power. B is the incoming signal, E is the amplified signal.

The O is the X in it is a lamp.

 

[MattPete]

Re: reading schematics

In Figure 2:
Same as Figure 1. The 12v thing is a battery cell.

http://www.kpsec.freeuk.com/symbol.htm
http://library.thinkquest.org/10784/circuit_symbols.html

 

[MattPete]

Re: reading schematics

I'm not going to try to explain all of figure 3, but here are the new symbols:

Capacitors. The ones with an n are in nanofarads, p = picofarads, and µ = microfarads

Polarized capacitors. If you put these in backwads, bad things happen.

resistors. k = kiloOhms. I think all of these are of fixed value, except for the one that says 1M-log Gain. That's a 1meg audio-taper potentiometer (variable resistor).

"Bright" and "Bottom" are switches.

is ground

U1 is a dual op-amp.

 

[cream123]

Re: reading schematics

In Figure 1:

VR1 = variable resistor #1, i.e. a 10k potentiometer
R1 = resistor #1, 1k ohms.
NPN = an NPN transistor. C provides the power. B is the incoming signal, E is the amplified signal.

The O is the X in it is a lamp.

alright ths is a start. I don't know why that happens though. (which wires supply this and that etc.)

 

[JB_From_Hell]

Re: reading schematics

Start with something more simple. Learn all the symbols, and the terminology (series, parallel, etc....) first.

 

[cream123]

Re: reading schematics

Start with something more simple. Learn all the symbols, and the terminology (series, parallel, etc....) first.

I know the symbols, and I knew some of the terminology once upon a time.

I think I'm starting to remember what parallel is. Isn't that where one part can be not connected but it still works.

The bright switch itself is series right? But then the wire that runs on top of the bright switch makes this part parallel, right? It sort of makes sense in my head but it's probably not right.

here's the area I speak of

 

[Artie]

Re: reading schematics

This is deep. MattPete has some good basics. Here's a start:

A transistor is just an electrical valve. You control current flow through it by adjusting the current control through the base.

btw - I'm not blowing you off here. Its just New Years, and all the crumb-crunchers just left. We're on our second bottle of Champa . . .Chem . . . Champgn . . .sparkling wine, and this will taker deeper thought than I have right now.

 

[cream123]

Re: reading schematics

This is deep. MattPete has some good basics. Here's a start:

A transistor is just an electrical valve. You control current flow through it by adjusting the current control through the base.

How do you adjust the base? is the base the amount of current coming? So would the amount of current allowed through the transistor depend on how much is put in? So the transistor has some fixed ratio or something?

That's cool, I can wait a while

 

[Artie]

Re: reading schematics

I can cover a little of this now. A transistor has a fixed "gain". You use a voltage divider, consisting of resistors, to control the current through the base. That, in turn, controls the current through the emitter/collector. Thats what's meant by "biasing" a transistor.

 

[MattPete]

Re: reading schematics

I know the symbols, and I knew some of the terminology once upon a time.

I think I'm starting to remember what parallel is. Isn't that where one part can be not connected but it still works.

Um, no.

The first two stages of a jumpered Plexi are in parallel (I'll label these A1 and A2). That is, your guitar signal is split, sent to two tubes, and the output of those two tubes are then combined back to drive another tube. That is, the first two tubes are working in parallel:

    /--A1--\
In -        >---B---C-->
    \--A2--/

Stages B and C are in serial. That is, B feeds into C.

The bright switch itself is series right?

[edit] Well, it depends by what you mean. The terms 'parallel' and 'series' are alway in reference to something (see below). The cap is in series with the switch, but...

the cap is in series with the 1M pot. When the switch is open, the signal goes through the 1meg pot. When the switch is closed, some of the signal bypasses the pot and goes through the 470p cap, while the rest goes through the pot (i.e. they are in parallel).

But then the wire that runs on top of the bright switch makes this part parallel, right? It sort of makes sense in my head but it's probably not right.

Yep, the switch is in parallel with the pot.


Think of it this way:

With the switch open, the signal flows in series from the 1n cap, to the 1M pot (some may go to ground here), then to the 470p cap and 470k resistor. The 1n cap and 1M pot are in serial, whereas the the 470p cap and 470k resistor are in parallel. Keep in mind that when we talk about something being in parallel or serial, we're talking about a relationship. So the 470k resistor in in serial with the 1M pot, but in parallel with the 470p cap.

Hope I didn't confuse you more.

 

[MattPete]

Re: reading schematics

How do you adjust the base? is the base the amount of current coming? So would the amount of current allowed through the transistor depend on how much is put in? So the transistor has some fixed ratio or something?

That's cool, I can wait a while

The base is your signal (plus any bias or other stuff).

 

[cream123]

Re: reading schematics

Think of it this way:

With the switch open, the signal flows in series from the 1n cap, to the 1M pot (some may go to ground here), then to the 470p cap and 470k resistor. The 1n cap and 1M pot are in serial, whereas the the 470p cap and 470k resistor are in parallel. Keep in mind that when we talk about something being in parallel or serial, we're talking about a relationship. So the 470k resistor in in serial with the 1M pot, but in parallel with the 470p cap.

Hope I didn't confuse you more.

You only confused me a little.

Concerning parallel: what makes parallel parellel then? Just that the signal is split into 2 parts and is sent through different parts compared to the other and then rejoins with the other? This is my main confusion.

However I think I understand the switch thing though. So the reason the 470p resistor next to the switch isn't included when the switch is open is that it is series with the switch then?

So where the 1M pot hits the 470k/470p intersection the signal splits? Then it rejoins when they come together before Q2?

 

[Artie]

Re: reading schematics

To help understand series/parallel, try to analyze simple circuits. Look at this:

Each LED is in series with one resistor. The three LED/resistor pairs are in parallel. That parallel group is in series with the switch which is in series with the battery. Closing the switch will cause full battery voltage to be applied to all three LED's. The total current will divide between them. If you have a 9-volt battery, each LED/resistor will "feel" 9 volts. If you have a total of 45 ma's, each LED/resistor pair will get 15ma's.

 

[cream123]

Re: reading schematics

Also when the switch is closed then 1M pot and the 470p cap become parallel right?

The 470p cap and the switch are in series right?

 

[cream123]

Re: reading schematics

To help understand series/parallel, try to analyze simple circuits. Look at this:

Each LED is in series with one resistor. The three LED/resistor pairs are in parallel. That parallel group is in series with the switch which is in series with the battery. Closing the switch will cause full battery voltage to be applied to all three LED's. The total current will divide between them. If you have a 9-volt battery, each LED/resistor will "feel" 9 volts. If you have a total of 45 ma's, each LED/resistor pair will get 15ma's.

That makes sense! :banana:

 

[gordon_39422]

Re: reading schematics

Might I suggest a home-study book from Radio Shack? Understanding Solid State Electronics is the title... I've had mine for years, but I think it cost me about $6... It starts of slow with analogies of water and moves on from there... by the end of the book, you should be able to understand and read complex schematics rather well!

I STILL have the book and refer to it quite often.... Well worth the $6