Correct symbol for a transistor? (URGENT!)

In article , snipped-for-privacy@ihug.co.nz says... | Basically, the question asked to draw a simple circuit, and within | this circuit was the symbol for a transistor. So I complied, and drew | it in, arrow pointing outwards (NPN transistor), and labelled the pins | (B,C,E). Now the transistor has a circle around it, and my circle was | drawn perfectly, BUT the tip of the arrow was not touching the edge of | the circle, and hence a mark was taken off. IS THIS FAIR? Is it | strictly defined to have the arrowhead touching the edge of the | circle? | |

In the standard symbol if it has a circle around it, then the tip of the arrow touches the circle. It does seem a bit mean to deduct a point though for a small gap in a hand drawing. The standard does not include marking the B, C, E pins.

If your line is not connected to the transistor then the circuit is a no connect. There are times that pins are no connects. You should take this as a lesson learned. And just for note I was involved in a product that the Eng. did something similar and we had 20,000 PCBs that did not work correctly. So the issue has real world consequences.

Well, others have made a couple of points. But here's my two cents.

For a *physics* course, the *hand-drawn* symbol should clearly show which direction the arrow points. And the arrow should be on the emitter. Also the base should be on the side opposite the other two connections. But to take points off for the arrow head not touching the circle is a bit over the top.

In EE, the possibility of a NC (no connect) might be considered, but if there is a line leading up to a terminal and stops just short of the terminal, that's ambiguous and would need clarification/confirmation.

As to whether this is 'FAIR', well, life is full of slights and unfair things. Is 1/27 of 5% of one course in one year of your schooling really

*that* important to society and the cosmos?? NO! Learn to accept such things and move on...

daestrom

On 6 Sep 2003 23:49:29 -0700, snipped-for-privacy@ihug.co.nz (Raoul) Gave us:

Actually, it is most often depicted today without any circle at all.

That was a nitpick in my opinion, and the teacher's character as an educator is in question, in my view to be such an old school marm prude!

On Sun, 07 Sep 2003 15:02:56 GMT, "daestrom" Gave us:

If he got 100% of it correct, he should not be chastised by the likes of you for wanting that 100% grade on his record.

Stupid answer.

My two cent below assumes the picture of what you are talking about that I have in my head. Perhaps I am all wrong in what you actually did, but here goes...

First of all, this is a physics class and not an electronics class. Second of all, it was hand drawn and without a stencil from the sound of it. If you were to actually go buy an electronics drafting stencil you would find that many of them do not have the arrow touching the edge of the circle but rather backed away from the edge intentionally. Others will have it touching. Many electronic articles that have schematics, particularly earlier hobby type articles, also do not have the arrow touching the edge... others do.

Whether or not your grade is fair is of course subjective. I believe it is not, and it may be worth it for you to pursue your case. It is not the single point that I personally would be after, but rather to nip the pettiness this instructor has applied to the application, in the bud. If you show your case and show you do give a s**t, he may reverse his decision and give you your 100%.

After all, if he is being so nit picky, would he not expect you to be the same way?

Some would have you believe that it would have made a difference in the real world, but I am here to tell you that if it did, you would be working with people that haven't an original thought in their head, or are thinking about the 70's when things were done more by hand then by computer. A slight gap in a hand drawn schematic should not be used to determine anything when laying out a PCB. If there was a question as to whether or not there was a connection to the transistor, someone should ask. If it was obvious, then it was obvious!

I just love a good instructor fight! I won many of them in college... and the instructor wound up as my best man at my wedding years later. Just do it with some class.

C

And that was a helpful answer?? Yeah, right.

Learning to live with minor things is part of life. Something *you* never seemed to have learned.

daestrom

On Sun, 07 Sep 2003 17:21:18 GMT, "daestrom" Gave us:

Yes, actually, it was as it should spur him on to dispute the scoring. YOUR reply was to cower in the corner like the little wussy that you must be.

It being "minor" is only YOUR opinion, you retarded twit!

I live with minor twits like you around me, everywhere.

Dumbfuck. It is the short version of the post where the guy describes all the stencils available.

As I have already stated, it is most often depicted without any circle at all in most schematic capture apps out there today, you retarded twit!

Yes, my post is right on the money, and you are a little girly bitch with no brains, and a mouth.

Right.....

Like you... he should go loose his temper and call the professor's character into question and alienate everyone within ear-shot over

According to IEEE std 315-1975 (ANSI Y32.2-1975) "Graphic Symbols for Electric & Electronics Diagrams", the arrowhead is not required to touch the circle. The only requirement is for the arrowhead to be half of it's length away from the base region. The circle may be omitted unless it is connected to the circuit or has a functional purpose. The sample symbols throughout the standard have arrowheads which are far from the circle.

Your instructor is wrong. You deserve the full grade.

Ben Miller

My two cent below assumes the picture of what you are talking about that I have in my head. Perhaps I am all wrong in what you actually did, but here goes...

First of all, this is a physics class and not an electronics class. Second of all, it was hand drawn and without a stencil from the sound of it. If you were to actually go buy an electronics drafting stencil you would find that many of them do not have the arrow touching the edge of the circle but rather backed away from the edge intentionally. Others will have it touching. Many electronic articles that have schematics, particularly earlier hobby type articles, also do not have the arrow touching the edge... others do.

Whether or not your grade is fair is of course subjective. I believe it is not, and it may be worth it for you to pursue your case. It is not the single point that I personally would be after, but rather to nip the pettiness this instructor has applied to the application, in the bud. If you show your case and show you do give a s**t, he may reverse his decision and give you your 100%.

After all, if he is being so nit picky, would he not expect you to be the same way?

Some would have you believe that it would have made a difference in the real world, but I am here to tell you that if it did, you would be working with people that haven't an original thought in their head, or are thinking about the 70's when things were done more by hand then by computer. A slight gap in a hand drawn schematic should not be used to determine anything when laying out a PCB. If there was a question as to whether or not there was a connection to the transistor, someone should ask. If it was obvious, then it was obvious!

I just love a good instructor fight! I won many of them in college... and the instructor wound up as my best man at my wedding years later. Just do it with some class.

C

26 of 27? Looks like you are doing quite well. Don't dwell on this issue. At least you know now not to miss that little detail. To me it does seem a little bit of a nit pick. Each instructor will have their own way of teaching so you have to try to give them what they expect. Perhaps the point is not so apparent. Maybe the instructor doesn't want you to be sloppy in these details. In real life it can bite you! John

On Sun, 07 Sep 2003 20:56:36 GMT, "daestrom" Gave us:

Nobody but YOUR lame ass said anything about anybody losing his temper, dipshit.

And ANY valedictorian student will not beg to differ with your retarded ass, he will laugh at your stupid remark. Guess what? Valedictorians are not "loosers", dipshit.

By the way, retard boy... the term is "loser". You know... what YOU are.

I think it was chicken shit. There is no requirement that the arrow touch the circle, let alone that a circle be drawn.

I have worked for a lot of pretty big companies and I have seldom seen a circle around a transistor on a schematic.

To be honest I prefer the old Canadian transistor symbol which I point out in my book. It consists of a line which is the base and two arrows coming into or out of the line. The arrows pointing in for a PNP transistor and the arrows pointing out for an NPN.

I believe it gets the idea of a transistor across better than the current symbol. Note the arrow pointing in or out was on the base line.

It gets the idea across that the transistor is really two back to back diodes across better and that the base region is really a part of a junction between two diodes.

I used it to better explain transistor action. . . I DO NOT FOLLOW MANY OF THESE NEWS GROUPS To answere me address mail to snipped-for-privacy@aol.com