How to substitute transistors?

[paulsherwin]

You can either melt the solder on a single pad and rock the transistor on the other 2 leads, or if the pads are all close together you can melt all 3 and just pull the transistor out in one go.

Different people will use different techniques though, depending on preference, experience, available tools and the components involved.

[Humber888]

Originally Posted by Radio Wrangler

There were also the D.A.T.A books.

They were VERY expensive back in the day, but gave one line's worth of parameters for an awful lot of devices. Rare as hen's teeth nowadays. I wonder if they've appeared on-line?

David

I've got a 1986 Transistor D.A.T.A. book that I rescued from work when it was updated. It can be very useful at times since the listings are organised in logic groupings and any transistor entry near the one to be replaced is likely to be a reasonable substitute. I think I have a diode book as well but haven't seen it recently.

I don't think these books have been produced for quite some years and I never found them on line.

Mike

[WME_bill]

How to substitute transistors.
I agree with MerlinMaxwell and RadioWrangler that the choice of substitutes is often wider than it first appears.
An indication of this can be gained from the Discrete Semiconductor Databook published by National Semiconductor Corpn of SantaClara, dated 1989.
It gives tables of the principle characteristics of most common US and Pro-Electron transistors, FETs and diodes, similar to the Towers books.
Then it gives fully detailed data sheets of their preferred choice types. As you can get from DataArchive or the manufacturers.

But the unusual thing is that it includes the Manufacturing Process type, which gives a detailed summary of characteristics of all transistors made by that particular chip design and manufacturing process.
Comparison with the detailed characteristics tables shows how the alternative type numbers have been selected for maximum working voltage, or gain or physical package and connections.

To illustrate how useful this can be, I attach this information for the 2N3904 family referred to by PaulSherwin.
As three files: 2N3904 data./ 2N3904 family data tables / 2N3904 family process 23.

There is lots more data on other transistor types, far too much to copy.
If anyone particularly interested in a family of transistors or FETs, I will look up the process family and give the pages suggesting alternatives.

This National Databook is over 1" thick and very comprehensive. One of a pile of ten National databooks covering semiconductors, linear integrated circuits, CMOS, TTL, etc, which I bought at a nominal price as a pile at the end of the counter somewhere in 1990. Perhaps from Cricklewood or in Edgware Road.

I also have various manufacturers listings, Motorola 1977, 1989, Texas 1972, Philips 1978, 1989 and 1995, Thomson 1995, Siliconix 1989, Intersil 1983, IR 1985, Ferranti/Zetex 1985.
Also listings 1976 by Jermyn Distribution (now Arrow) which gives several makers sorted by peak voltage rating and power.
And the other publishers listings, including Semicon International (mainly European) and the DATA books (far too bulky and mainly US). My Avo Transistor Manual is probably a very early edition, for it is extremely limited in scope, mainly germanium.
The Towers remains the most useful (1st and 5th editions).

I acquired all these by writing around when I was much younger or a student, and from skips as they were being thrown out at work.

What do people think I should do with all this information now. It seems a pity to skip it ( my wife is after me for a clear out). Too much to scan and publish.
And there does not seem to be a library covering semiconductors comparable with the invaluable Frank Philipse for valves/tubes.
wme_bill