Choosing "widespread" parts

Question

Many times I know the parameters of a part to choose and find hundreds of them, but I don't know which ones I would have to order, which ones I am likely to found in a local electronic parts store, and which ones are likely to be in every parts store and are much cheaper than the previous ones.

Say I need an NPN BJT with collector-emitter voltage of 1,5 kV, collector current of 2 A, collector peak current of 10 A and dissipated power of 6 W. Searching suitable transistors and checking each one whether it's present in a local store's price list takes a very long time. So how do I choose a suitable transistor that's likely to be found in most electronic parts stores?

Answer 1

In this case the decision is fairly easy. Try a major supplier's part selector and select the parameters of interest.

As an example I went to Farnell to set the selector for Vceo=1.5kv.

It's not an option.

So you're not looking for a "widespread" part at all. By all means keep looking and if you find a suitable part, buy it regardless of source. (If you have any doubts about the source, consider doing a lifetime buy.)

Or learn from this little experiment and change the design approach.

There are ways of operating devices in series to achieve higher voltage : they are complex and relatively difficult to get right (for obvious reasons...)

There are devices with higher breakdown voltage (even from Farnell); but they are not BJTs.

Or you may find another approach such as restricting the working voltage to 1kv.

Answer 2

You can use online parametric search engines and then sort by in-stock quantities to get some clue as to the most popular parts in the industry. Especially good if there are multiple sources for the same part and/or other suitable parts that are pin-compatible.

A more subtle thing is the intended applications for the parts. If they're mainly used in a fickle market such as cell phones or a dead market like CRT displays ( think horizontal output transistor in your case) they may not be available next year, or they may be bought up by speculators in the gray market and resold at many times the original price.

Answer 3

My approach is that for parts of the design that are likely to pop up in other designs I choose a component that is a good compromise between suitability, price, and availability, and is likely to be suitable for related purposes.

But this requires some searching, and the component will likely be overkill for at least some of its uses. If the price is low and does not vary much when you relax some parameters this is still a good idea.

For a component for which the price depends critically on its parameters, and for a use that is not likely to be repeated in other designs, you are probably stuck with finding an optimal choice for just that design. That takes time, no escape from that.

Do you even have a local parts store? I just order from a webshop (Mouser being my preferred choice because they are fast, and don't ask whether I am an active member of the communist party and/or will use their parts to build a nuclear attack drone), others might prefer DigiKey or AVnet or whatever.