Schematics & standards

ha, plus every damn wire is taped together into some completely awful harness. There has to be at least 50 pounds of PVC electrical tape in every car out there.

I'd rate this schematic as weird. Some parts are identified, some aren't and the junctions are complex for no reason.

Who photocopies stuff anymore, and periods aren't hard to read and never were, except in places that read right to left and switch periods to commas.

Banks don't print money is formats like 34$00. "Oh it's hard to read" is complete crap.

What's next- the germans and dutch replacing numbers with spelled out words?

I'm surprised the diodes past the output stage aren't indetified as something like:

or something just as goofy.

Why are the speakers just 6 ohms, while other resitors have place holders for digits?

I just don't get it- how does using multiple systems to represent simple data make things easier?

This is why the finest and best technology comes from the USA. Instead of trying to rewrite a 20nm process in semiconductor manufacturing as 20nm0 like europeans might form a committee to try to do, we've come out with

Just curious, has a committee come up with some cool new way to write voltages too?

The amp uses +/- 30. Should that be written as 30v0 and (30v0) for the negative rail?

Afer all, a "-" sign is too confusing and might indicate and error that was crossed out, or a period that was damaged during a recent facsimile transmission of poorly risographed copy of schematic.

Is 5kV now 5k0?

People often distribute low-resolution scans of printed circuit diagrams or print them out on poor printers. Sometimes it is almost impossible to read the figures, let alone distinguish a tiny dot.

Actually the currency sign often comes first, which is a long-established convention but very confusing the first time you meet it.

The loudspeakers are nominally 6-ohms impedance (but actually much more complex), so the markings on them aren't really component values - more like a part description.

Which resistors only have place holders? I can quite believe that i have made mistakes in the drawing, but I haven't spotted that one.

I don't know if the convention was imposed on industry by a committee or whether it was adopted by industry because it was found to have advantages in certain circumstances. I agree that we sometimes have too many committees, but most of Europe (except the U.K.) has acquired the skill of appearing to comply with new regulations whilst actually ignoring them.

I think you may have (deliberately ?) misunderstood the reason for that convention. It saves space on small components and is unambiguous. There is no need to use it for voltages (although "1v1" is easier to write than 1.1v and less likely to be mistaken for 11v).

The convention of three numbers ("104" = 100K) is even smaller to print but the interpretation is not as obvious until you get used to it.

They do tend to give a slightly messy appearance, but the alternatives were worse:

Can you really not understand it ? Or are you being deliberately obtuse ? It has now been explained to the point where a child could understand it. I think it was actually me who you first saw using it here, and I'm pretty sure that we went through it all for your benefit at the time ...

Arfa

It's been around on this side of the pond for many a year. It uses fewer characters and no chance of not seeing that little full stop in a poorly copied diagram. Like everything else you need to get used to it, though.

No they don't.

You guys talk about faded photocopies and the usage of 2.2K vs. 2K2, it ever occur to you a faded photocopy of the BassAmplifier2.gif, those transistors come out looking like diodes?

I'm with Dave, I never seen that either.

Plus, what the hell is the S-N-U on the tip35c's and R-G-O on the tip36'c?

I can't find a single datasheet for them that uses anything else besides E-B-C.

That diagram is terrible.

-bruce snipped-for-privacy@ripco.com

Perhaps, but there aren't many diodes with three wire connections that they could be mistaken for. The direction of the arrows might be lost if they became blobby, but so would the arrows on the point-contact symbol.

It is unusual nowadays, but if you had been designing in the 1960s you would have come across it from time to time.

Slate-Brown-Blue. Red-Green-Orange. It is the colour code of the wires. The output transistors are mounted on individual heat sinks and connected to the rest of the amplifier by a wiring loom, so the colour code is helpful for fault-finding.

I didn't think there was any need for E-B-C as that should be obvious from the symbols.

We were discussing our preferred symbols and that diagram illustrates my preferences. My personal dislikes are:

2) Transistors and valves shown as a collection of electrodes floating in space without envelopes.

For an example of a truly horrible circuit diagram see:

When re-drawn it makes a lot more sense: <

The symbol for an adjustable zener, used typically in switch mode power supplies, looks pretty similar :-)

Arfa

That's OK for digital work, but for RF or high Z, your capacitor symbol needs to have one line, one curve, as appropriate.

Another subtlety: if the tube symbol has a dot, it's OK to see a plate glow. No dot, that glow means ... too much current.

Americans also do crazy things like just write a + sign next to the anode if two parallel lines of equal size are used to represent a capacitor.

On the other hand, only the cathode is marked on electrolytics for some reason. Is there a great story behind this?

That's funny as writing out values the correct and conventional way doesn't need explanation and a child can follow it, and it's been that way for decades.

I'm still waiting to see values for money being written out as 44"euro symbol"66 with cents after the end instead of 44.66.

periods are too confusing, commas are too confusing! help, we're all stupid these days!

I saw an original diagram for a bass amplifier earlier in this post.

it looked awful and it wasn't a copy. The text annotations looked like they came from a 9 dot matrix printer and were small and hard to read. The transistors looked lopsided and weird too. That's how it was from the start.

I've seriously seen wet-type microfiche printer printouts that look better and are easier to follow.

Getting bored and changing how you do stuff every few years doesn't make schematics better looking, eaaier to follow or less ambigious by itself.

So, when do you start to write 1.5km as 1km5?

hahaha.

the "awful" schematic is great. All it needs are euro-notations, then to be rendered in a small terrible font then saved as a gif.

On 6/20/2010 7:06 AM Adrian Tuddenham spake thus:

Agree with this 100%. No need to be so chintzy!

That's an excellent suggestion. Your first?

As an aside, what is it with people who seem to feel they have a god-given right to dictate the 'right' way to do things? If they had their way, we'd still be walking everywhere, and seeking shelter in trees at night. Things change; usually for the better, sometimes not. Deal with it.

PlainBill

OK then. You started going on about writing voltages in that notation, as though you couldn't understand that either. Do they not sell zener diodes in America ? That notation has been used for as long as they've been around. Like BZY88 C6V8. Have you never seen that, or perhaps you've never understood what it meant ?

Arfa

Seconded

Arfa

On 6/20/2010 5:33 PM Arfa Daily spake thus:

Actually, I think you misunderstood *him*. He was saying that if you're going to use that strange system for resistances, why not also use it for voltages (or perhaps any quantity) as well? Instead of 5.6 volts, since you're so all-fired worried about the potential loss of a period (sorry, full stop), then you should write it as 5V6, no? Or something like that.

I agree with him. Why the concern about potential loss of decimal-place information regarding resistances, but not for other parameters like voltage?

I think this whole system is needless, and therefore needlessly obtuse, no matter that people like you may become accustomed to it. How often does a decimal point actually disappear? Seems as if schematics were drawn the old "bad" way for decades, and I don't remember any big hullabaloo about mistaken resistance values.