ephemt as diode

If you like things that have no bearing on reality (nudges about politics?), then fine. The original symbols were created because they had meaning. Arrows mean PN junctions. There are exactly zero [original] symbols where this is not the case. JFET, MOSFET (the one with the substrate arrow), BJT, diode, SCR, TRIAC. It's a sub-language all its own.

Going back still further, vacuum tubes did the same thing. Heater-cathode: just a "^" or squiggle. Unipotential cathode: a flat thing. Gas-filled unheated (or passively heated) cathode: round circle. Grids, deflection plates, anodes, etc., all standard.

Early tube symbols had a less abstract shape (like a tight "V" for the filament/heater, and squiggly grids). I don't know about the history and motivation of that change, though I certainly appreciate the simplified, abstract symbolism they moved to.

Hah, IEC or DIN is if you're in Europe anyway. You're trying way too hard. Which means I've created cognitive dissonance, which means you understand the point I'm trying to make, and you're straining to come up with excuses to reject it. :-)

Most recently I've adopted the tradition of using yellow boxes (which is ultimately Altium's default, but I don't mind) to suggest integrated circuits, and a similarly light shade of blue to suggest discrete components.

So I might box the "zener" in yellow, or fill the triangle with yellow. Best of both worlds, and utterly deflates your attempted sabotage. >:)

Here's an example with old-school parts:

(By convention, the cathode comes off to one side, and the grids are closely spaced, which is kind of awkward on modern grid-based schematic entry. These feel like a reasonable compromise. The symbols are multi-part, so every "A" has a "B" which is the heater part. All the extra suffixes look ugly, but that's an EDA limitation.)

Of the hand-drawn variety -- black and white only:

Really, for TL431s, I would prefer something descriptive, like an NPN transistor with a base buffer (since it draws little input current) and very accurate Vbe (indicated... somehow). But if you want to at least throw doubt at the reader, a cryptic box is about as good as any. I've used that before, too.

Not all are made alike. The LM4040 series are apparently PNP types. But they don't spec them that way, so it's dubious to use them for anything other than static reference. A shame.

Hah, standards. The wonderful thing is there are so many to choose from!

Anyone who would willingly choose or suggest IEC or IEEE is presumably a fool... especially in the US.

You'll notice I have no care for explicit standards, and made no mention of them in my prior appeal. I only care about readability, and reading the symbols themselves is part of reading the schematic as a whole.

As for layout standards, I wrote my own, so I don't have to worry about others. You'll find very similar suggestions in AoE and others, where readability is cared for (their unfortunate choice of "NPN" MOS notwithstanding).

Tim

--
Seven Transistor Labs 
Electrical Engineering Consultation 
Website: http://seventransistorlabs.com

Which copy goes under ECO control?

Well, just draw everything as boxes. Or maybe circles, with uniformly angled radial leads. Or do like the digital boys do, just type text.

What that circuit needs is a couple of p-channel tubes. And output

*on*the*right*.

And then you can make your own!

It was a big deal once. So was Pascal.

That's why I drew the phemt, and mosfets, the way I do. They look like transistors with insulated bases.

H+H are very sensible gentlemen. Especially on page 360.

How do you feel about four wires meeting at a dot?

Don't have one. But there are all sorts of tricks you can play with pulses and resistors. Sometimes you can learn a lot from TDR, too.

I don't think the gate is conducting, not at 0.4 volts, but it is turning the channel on. Besides, the gates on these parts would vaprorize at the sorts of currents that I'm running through them. The gate metalization is apparently delicate.

In the lower case, the positive gate voltage turns it on and the current is going through the drain. The gate itself wouldn't conduct until about 0.7 volts or so. What's neat in that case is the negative swing.

The upper case is the same if you assume the device to be symmetric.

The ATF50189 data sheet finesses the schematic-symbol dilemma by not drawing it at all.

My vellum is just kept as a reference, because it often has notes or waveform sketches or other stuff that doesn't get to the CAD schematic. Of course the official, controlled drawings are the CAD stuff.

I just find it a lot easier, and more fun, to draw with a pencil. It doesn't slow me down if a library part hasn't been created and checked and released yet... I just draw it. I designed my office so that my drafting table has a view:

It's good to get away from a screen and draw and solder and cut metal once in a while.

As long as your printer is better than Panteltje's, what's the problem? It's when the four wires meet without the dot that problems occur.

I sorta figured but some try to keep two documents controlling a design. It's impossible to keep them in sync and then both are likely wrong.

I just take a similar part (perhaps with only the same number of pins) and drop it in until the CAD group gets the right part in the library. It's then a simple matter to replace the bogus part.

It's nice to be the boss. I have a white wall. ...and I'm one of the lucky ones.

Not often enough for me. Everything is in the same cube (though EE's get about twice the floor space as everyone else).

On Dec 19, 2015, John Larkin wrote (in article):

text

assume

will

Ahh. You need to let the camera in on the secret. It has no idea what you are photographing, and so assumes that what it is viewing is on average 18% gray, not 95% white. I don?t know the make and model, but there will be a way to tell the camera that the page is 95% white. This is the same problem as taking pictures of snowscapes - the snow comes out looking dirty - grossly underexposed. Generally, one opens the camera up by two or three stops to fix the problem.

Your CAD guy probably does not think that the drawing is 18% gray, so no problem.

Joe Gwinn

After my sketches are CAD'd, they get tweaked a bunch and design reviewed at least twice. Eventually they are formally released, with the layout and BOM and all that. That's a formal path.

Our BOM does supercede the values on the schematic, one reson being that we can have multiple dash number versions.

I also walk around, and climb stairs, to get a little exercize. Like use the bathroom on the ground floor (I'm on 3) or something like that. Walk to talk to people in the building instead of using the phone. Engineering is too sedentary.

I've use several cameras, all just set to Auto and often Macro. I use Irfanview to crop and tweak contract, sometimes sharpen.

I have a working blueline machine!

I've found them useful enough that I once spent all night downloading the . s2p files for every SMT filter they sell, and spent the next weekend hackin g together a program to view their cascaded responses (

m/s2plan.png ).

It's pretty handy since their filters' part numbers are only vaguely correl ated with their actual cutoff frequencies. Also good for anticipating and dealing with reentrant behavior.

Amusing... I remember the ERA-5 debacle. In fact, I may have been one of t he first customers who complained about it. They were hesitant to believe me when I told them their latest batch of ERA-5s was oscillating at about 1 kHz, so I built a buzzer with one of them driving a 2" speaker and sent it to them, batteries included. Never heard anything else back from Mini-Cir cuits, but the problem was fixed by the next time I ordered some parts from them.

It apparently turned into a lawsuit against Sirenza (

) over th e definition of "unconditionally stable." I don't know who eventually won, but I sure as heck hope it was Mini-Circuits.

-- john, KE5FX

Auch, no! Did you not get anything about the "it should describe what it is" part?

Maybe you're just bad at reading...

I'd draw you a diagram, but that would apparently leave you even more lost... :-D

Yes. Well, the P-channel part. In drawing that (and a couple of others), I've realized it's actually a very... interesting design challenge to make up for the lack of P-channel.

Shitty lateral PNP is a luxury compared to doing a tube-state design exercise!

Output doesn't really matter, because it's also the input. Eh? EHHH???

Altium is still written in Pascal. Well, it's successor, Delphi. Welllll... supposedly they're *FINALLY* moving away from that ancient codebase and porting it to C++ (and 64 bits).

BASIC was once a big deal, too. And FORTRAN.

Apparently COBOL was a big enough deal that companies are still paying for poor suckers to maintain their filthy codebases. The world works in mysterious ways...

Except you can't insulate a base...

Ah, staggered.

I probably have more than a few exceptions in my archives, but especially these days, I try.

Again: readability and understanding. If it doesn't improve either, it's dumb!

Tim

--
Seven Transistor Labs 
Electrical Engineering Consultation 
Website: http://seventransistorlabs.com

Current Delphi/XE/FPC/Lazarus Does 64 bits and also dose cross platform compiles with little problem. This means OSX, Andriod, Linux. The FPC does more.

Code output is the same as C++ but a lot fewer bugs cropping up from case sensitive for example, like in C/C++. The tools operate much faster then VC or any C/C++ compiler IDE setup from what I've seen. Plus all these Pascal type compilers are also supporting the latest Unicode families etc..

Why would anyone take a package with so many hours of work in it and get hardly nothing in improvements by switching over to C/C++? If switching to .NET is their plan, then you may want to hold on to that idea because most of the issues that pop up are those that MS have to fix and they do that when they get around to it.

Do remember that current Tools still compile to native, not .NET not C# and not any of those multiple overlays of libs that put lard on the system.

Just my opinion, really, but formed from experience of many others and myself.

Jamie

Looks like there's a pretty high impedance looking into that terminal, what's the impedance looking into there?

Y u no decouple screen supply?

----Android NewsGroup Reader----

On Dec 20, 2015, John Larkin wrote (in article):

played

little

grey)

person

to

The solution is relatively simple - most modern digital cameras have a Snow exposure mode, so try that. Otherwise, Irfanview may not have enough to go on, it that it wasn?t really designed for text and line drawings.

Joe Gwinn

I always enjoy schematics that have that little hump in the wire where it crosses sans connection. Has that nice old-school feel to it. Almost like the schematics where "condensers" are stated in mmf and megahertzes are megacycles.

--
Regards, Joerg 

http://www.analogconsultants.com/

If reading old-style schematics makes you feel young, you must be ...? ;)

joe

...feeling young?