Couple of millennium bypass questions.

[Hambo]

I've been lookin at this, and it seems the later versions of the millennium 1 are the way to go for me, being small n easy looking, and dp3t switches seem to be rarer than rocking horse shite in these parts.

I'm not in need of any great mail order amount of stuff for anything to build right now so I after a quick look at the ever useful Craplin website, the staggering array of J-FETS available are as follows:

       V      mA     mW    Style
BF511   20   7   250   SOT23
BFR31   25   5   250   SOT23
BFR30   25   10   250   SOT23
BF245C   30   25   300   TO92

I've never seen a J201 anywhere, ever, even in any of my countries mail order electronics places.. a constant enragement to me.
So I presume this BF245C will work? Any insights on this? any other considerations blatantly apparent to the more experienced potchers?

Secondly, I have 2 pedals which run on bipolar power supply +-12v I cant see why the same wouldnt work there connecting to +12v and common?

Actually it occurs to me I know sod all about LED's theres 5v and 12v available, which do I use?

Thanks all.

[R.G.]

You know, we're having a shortage of rocking horse shite here in Texas, too. 

Don't get the others, they're surface mount. You want the TO-92 package.

Some BF245C's will work. The datasheet on the BF245 shows the three types of A, B, and C have different values of the cutoff value of gate-source voltage. They tell you it's from -0.3V to -8.0V for the whole mess, but they don't say what it is for the A, B, and C.

But they do mention that the "C" will be shut down below 200uA by a gate-source voltage of -3.2 to -7.5V. That's the critical voltage - you have to have the gate cutoff voltage plus your LED voltage be less than your power supply. Since you're using 12V (yes, that will work) you're better off than us guys with only 9V supplies.

So grab a few BF245C's. Some will work, probably.

[Hambo]

What you say is very interesting RG.

I can nearly feel my brain almost understanding some stuff. So the cutoff voltage varies widely for these and If i can find a fet with a more definite cutoff range, the lower the better.. can it be too low?

By LED voltage do you mean the forward voltage? that would mean MOST of these BF245s should work ok, especially with the 12v pedals... Also as this is different for various LEDS if I remember right.. So I could use the lowest Forward voltage I can find, and make it slightly more likely to work with the 9v ones?

[slacker]

to be honest you might as well do the millenium 2, you can get 2N7000s from Maplins. If you want to keep it simple just leave out the low leakage diode, I've done that a couple of times and never had any problems.

[Hambo]

Point Taken. I will do this. I didnt realise they had those 2n7000s, thanks man.

What resistor values did you use out of interest?