ВЭФ 12 (Astrad VEF 12 Project) - including a transistor tutorial

[Nowhere-Man]

Mark says his learning electronics in the early years came from a number of won battles. For me, it's more a feeling of trying to win wars. Sometimes I feel I could lose these wars. Tonight my battle was to do with the same thing - anode current and resistance applied to voltage. After this battle I feel typical current for a triode heptode like ECH1 is about 3.5 or 4 milliamps. I know the triode anode voltage is 95 volts because it's in the tables. The current has been listed on sites up to 13 milliamps.
The other question I will come back to.

[Nowhere-Man]

Yes, Miguel, I found your accounts of P and MP substitutes and it looks like I will have to do the same. The Russian engineers shrug off the idea of trying to get germanium transistors. I only wanted a few spares. However, maybe places like Tomsk could have NOS. For now I will try equivalents. And test further. On the Russian forum my post seems to have been relocated because maybe they found it strange an English guy appears asking about the VEF12. Plus not many foreigners these days want to learn Russian. Spanish is more popular these days, more than French I guess.

[ppppenguin]

What do you mean by tables? From context I think you mean circuit diagrams, or schematics as they're often called these days, but it's confusing for the rest of us.

[pwdrive]

Mark says his learning electronics in the early years came from a number of won battles. For me, it's more a feeling of trying to win wars. Sometimes I feel I could lose these wars. Tonight my battle was to do with the same thing - anode current and resistance applied to voltage. After this battle I feel typical current for a triode heptode like ECH1 is about 3.5 or 4 milliamps. I know the triode anode voltage is 95 volts because it's in the tables. The current has been listed on sites up to 13 milliamps.
The other question I will come back to.

If you're referring to the ECH81 in that Saalburg 5170 then you're not far off, switched to AM I make Iat 3.7mA and Iah 5mA.

EDIT: Regarding the 13mA figure, sometimes it's easy to get confused when reading valve manufactures valve data, for instance in the ECH81 data listed here: http://www.r-type.org/pdfs/ech81.pdf in the valve characteristics it lists Iat as 13mA but that is with no voltage on the grid, that is a static figure eg: the triode not operating as an oscillator, when it's operating as an oscillator the grid voltage will be -ve and hence Iat will be less.

Lawrence.

[Crackle]

Hi NWM
The data in the valve manufacturers specification sheets is mainly for guidance, it gives the maximum operating conditions and often some examples of the valve under different conditions.
You should accept that in each different radio the circuit can be different depending on the manufacturers preferred way of doing things.
If the measured voltages in your radio are different to the valve manufacturers it does not always indicate a fault.
Personally as I am in the UK I try and stick with British made vintage radios where plenty of service information is readily available and most of the service sheets specify the particular operating voltages for each valve.

I have observed that you must have read up on a lot of very technical electronics subjects, many of which seem to have taken you far and beyond what is needed to have an understanding of how a radio works and how to fault find. I am not surprised you feel like you have been fighting "wars".

What you need now is to completely put to one side the advanced technical stuff and gain lots of practical experience in the basics and to listen and learn from and acknowledge the advice given to you on here. Ohms law and a basic understanding of the function (not the chemistry or method) of each type of component is all I really use when I am working on a radio, not "holes" and nuclear chemistry.

On another note, it would be nice to think of you as a named person rather than NWM all the time, I like to sign my name to my posts.

Mike

[Murphyv310]

Excellent post Mike. Going too deep without knowing the fundamentals will not only confuse you but it can often lead to making horrific mistakes. Like Mike I always sign off as in my signature seen below.
I'm the first to admit that I can be to the point that some unfortunately can't cope with but if I feel something isn't right I'll tell you, I'm honest and surely that is better than being patronizing.
Like I've said before get to grips with the groundwork and put the textbooks aside and don't theorize when you don't have a proper knowledge of the basics.
The chaps here will give good advice and it will help you so long as you follow their help and don't go off on a tangent.
Oh and it would be nice to know your Christian name.

[Nowhere-Man]

My Russian is similar. Very complex sentence structure but not the way conversation is. Many oldish words the younger Russians don't use. Now I am in the stage of learning the technical language which is a good idea. It's a pity there's no money in it. It is a fair point though you can overload. Radio is very broad so you just specialise in one area like ACDC bakelite or HAM.
As to "holes" how many were in Blackburn Lancashire?

[pwdrive]

Collectoreo, collectoreo, where for art thou....

Lawrence.

[Nowhere-Man]

Been corresponding with a few Russian hobbyists. I was given a few links to check. I don't use Ebay at all now and want to seek out components directly, including electrolytics and other items.
Not sure either how the electronics industry is doing in Russia. The satellite and defence industry is probably no 1 now in the globe but I suspect other countries like Japan and China lead in audio electronics.
The USSR trannys I rate pretty high but Japan better understood consumer requirements.

[Murphyv310]

Don't dismiss the role the UK has in Audio, companies like Linn. Creek, Chord, Naim, Epos and many more are far superior to what comes out of China.
The Chinese are well known to copy others ideas, my daughter has first hand experience with this as one of her textile designs was stolen at a textile fair some years ago and is now on a famous brand.
Quad unfortunately along with other companies get their product made in China to reduce production costs, the British worker then looses out.
Japan was also a very innovative country with companies at the forefront of technology and research, I worked for instance with Sony and they were brilliant to work with, their training was second to none and the Japanese lecturers were excellent.
The Russians are a force in Electronics. In fact the 625 line system is now reckoned to be a Russian devised system and not German. They also carried on with valve technology and designs long after the west abandoned valves. They did though lag well behind the west in semiconductor technology and their computing technology also lagged behind us, they were and are some of the best programmers and have software that can run on basic machines, not common and not really known in the west either.

I'm not so sure of their military equipment these days as they have financial problems like us, they have a lot of old kit but unlike us they do maintain it whereas we scrap a shed load of stuff, just go to the government sales and you'll see how much military equipment we ditch.
Military equipment from the old USSR that is available to buy is mind boggling, It's easy to find and buy but it "is" old now.