Blue Ring Tester Error???

[PC@live]

Blue Ring Tester Error???
Hi all, looking at the diagram of the testers, I noticed a mistake???
The Q1 = 2N3904 transistors in the "Parts List" is an NPN.
However, the schema is connected to +, so it should be a PNP??? (Perhaps 2N3906???)
If it is a write error (2N3904 transistors instead of 2N3906) then Q2 and Q3 are PNP???
If someone can explain to me, if there is an error.

Thank you so much who can help me to understand Yours

[Radio Fox]

Re: Blue Ring Tester Error???

The collector of Q1 connects to the +ve supply which is correct for an NPN transistor.

http://electronicsclub.info/transistorcircuits.htm

[PC@live]

Re: Blue Ring Tester Error???

The collector of Q1 connects to the +ve supply which is correct for an NPN transistor.

http://electronicsclub.info/transistorcircuits.htm

Thanks a lot.
The question I had come because the Tester LOPT/FBT, Q1 was a PNP.

Greetings

[budm]

Re: Blue Ring Tester Error???

It is shown as PNP per diagram that I have, it is also indicated as PNP in the BOM.
The Emitter is connected to the B+, it is setup as a simple amplifier to drive low Z load.
Do you have your diagram?
The later version has 3 transistors, all NPN.

[PC@live]

Re: Blue Ring Tester Error???

It is shown as PNP per diagram that I have, it is also indicated as PNP in the BOM.
The Emitter is connected to the B+, it is setup as a simple amplifier to drive low Z load.
Do you have your diagram?
The later version has 3 transistors, all NPN.

Yes, I have both the diagrams.
In fact Blue R.T. it seemed strange that the transistor Q1 was an NPN.

Thank you very much
Greetings

[Radio Fox]

Re: Blue Ring Tester Error???

It looks like the Blue ring tester has been modified/improved since the first version of the LOPT/FBT meter.

[tmiha71]

Re: Blue Ring Tester Error???

@Radio Fox

The page you posted is pretty messy. Heading is Transistor circuits, and it speaks of Bipolar-Junction Transistor, commonly named BJT. To be more specific it speaks of “common emitter” circuits. And this is, only, partly true - page speaks of BJT as switch, and probably, if you follow advices from page you WILL burn BJT.

Page lacks basic things, and can be recommended as funny (practicing) page about BJTs as switches (be carefull, if wrong things are learned, much more time is needed to learn things right). For any serious speak/work, only books by Jacob Millman, or books which references Mr. Jacob Millman books, should be recommended...

And yes it takes time to read books, but it's worth...

Probably Wikipedia should be recommended, at first, if web is source of information, but I like books...

[Radio Fox]

Re: Blue Ring Tester Error???

The only reason I linked to that page was to show how a NPN transistor should be connected with reference to the supply. It was to show PC@live that the Blue Ring Tester circuit diagram was correct.

I think that link shows the basics of how a bipolar transistor works pretty clearly for different types of use.

I doubt that Jacob Millman is the only author who knows how transistors work!

[tmiha71]

Re: Blue Ring Tester Error???

Mr. Jacob Millman, is authority, one of the pioneers of solid electronics/microelectronics, and I will have doubts in any book which omits his work/lectures.

That link shows how to use BJT as switch, and only as a concept (idea, as you said - basic wiring diagram). No other types of transistor circuits (usage?), and there are few more... To emphasize - title of the page IS misleading... And (that) page deserves pretty decent rewrite/redesign...

Yiiek, I am repeating myself.

[budm]

Re: Blue Ring Tester Error???

"page speaks of BJT as switch, and probably, if you follow advices from page you WILL burn BJT.'
Can you please clarify bu that transistor will burn? It is used as load sink for the load.

[Radio Fox]

Re: Blue Ring Tester Error???

Mr. Jacob Millman, is authority, one of the pioneers of solid electronics/microelectronics, and I will have doubts in any book which omits his work/lectures.

That link shows how to use BJT as switch, and only as a concept (idea, as you said - basic wiring diagram). No other types of transistor circuits (usage?), and there are few more... To emphasize - title of the page IS misleading... And (that) page deserves pretty decent rewrite/redesign...

Yiiek, I am repeating myself.

If you are taking a Ph.D. course in electronics, then perhaps works by Jacob Millman are recommended reading, but that's not what we are talking about here.

We are talking about a basic transistor circuit. To say that you would have doubts about anyone, other than Jacob Millman, describing how the basics of a transistor works is absurd! There are hundreds of thousands of people around the world who could correctly describe transistor basics.

To dismiss anyone else's work is very short-sighted!

I agree that there are omissions from that page I linked to (there should have been a linear amplifier circuit).

[tmiha71]

Re: Blue Ring Tester Error???

Page lacks any information about dissipated power... Minimum what should be there, is - max. allowed power dissipation (package dependent)... And not knowing that leads to fried BJT :-))
Introduces saturation, and yet neglects it ( saturation voltage is low /page says/, it's not, it is specified in data sheet of device).
There's no info about base losses, Ib x Ube...
There's no info about switching losses (in some occasions they are dominant, or are they always dominant, can't remember, must check, don't have any Millman book, but have few which do reference his books for further/detailed information )...
There's no info about switching time (does have impact on switching losses, less time leads to lower losses)...
At first, wikipedia should be recommended (didn't checked if there is any word about bjt's), more people reads it, and error/misconception will be “pretty fast” corrected (hopefully)...

Sorry for going OT...
PS. (for sure, on that page, there are a few more "half" informations, like Rce, like 5 x hFE... and a VERY GOOD book should be consulted to correct all things)...

[budm]

Re: Blue Ring Tester Error???

If you want to do actual design of the circuits then you will need more info to meet your design requirement, basic info is just that, simple term just to explain how it works.

[tmiha71]

Re: Blue Ring Tester Error???

@budm
page is a mess of information, any book will do better than that page.
-----------------------------------------------------------------------

I'm tired of defending books from web-based information (and web did brought, at the moment, only ONE advantage, and that is AVALABILITY)... Once more...
Mr. Millman is suggested because (do not want to repeat myself, few new thoughts):
1) did worked/lived in USA, practicing solid electronics
2) USA do have strong semiconductor industry (or do not have ?)

People which do/did work/ed in industry, did met his books (at least, if did not red them) -> so his books ARE GOOD ( in terms of simplicity to read, and accuracy of information )...

Actually I do not understand this reluctance toward books, especially - this book is for this, and that book is for that, books are to be used on daily basis. And with books it's possible to read one, and find that knowledge acquired will never be used (not because it's wrong or outdated, but because it's not needed)..

Sorry for being devil's attorney... Sorry for OFF TOPIC... I do put books before web... (Probably won't defend books for a quite some time, had to dig out few OLD books, do fast search, fast read, make long and tedious post.)

[MDOC]

Re: Blue Ring Tester Error???

For future reference when looking at schematics, it's easy to tell an NPN from a PNP:
NPN = "never pointing in"
PNP = "Pointing in"