Re: TIS98 and TPS98 transistor questions

<snip extremely useful info>

MANY thanks for that, marvellous stuff - I'll have to re-read it a few
times to *fully* understand it (I'm still learning, remember :) but it's
great. Hopefully it will also be of use to others on this list.

>What does it all mean? Use a fairly fast (over 1 MHz) NPN transistor
>with good gain in the 1-5 mA range and a voltage rating of at least 40
>volts (the more the merrier). Whatever you use USE THE SAME THING FOR
>BOTH Q701 AND Q702. Why? You want these two as close to matched as you
>can get. Most important matching is emitter to base voltage. If these
>aren't the same you get something called "offset voltage" which will
>cause centering to be off. With no offset voltage, zero voltage from
>the game board will give you zero current through the yoke (and that's a
>good thing!).

So now all I have to do is check the data sheets again for the 2SC2240 and
see how it matches up to your recommendations. Sounds easy? Well, it would
be if only for the fact that the sheets don't indicate the speed of the
transistor (or it's more than likely I'm reading them wrong!).

Re the gain - as I understand it, this is represented by the hFE
classification, is that correct? If so, my 2SC2240's are GR classification,
which according to the data sheet is 200 ~ 400. How does that equate to mA
then?

All the small transistors are the same type (they were previously TIS98's,
now they're all 2SC2240's) so all will match up.

Many thanks for your excellent help,
Phil

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Received on Mon Jan 21 14:40:31 2002