Only TWO to go....

Hi,
well I've spent just about 2 days on this, but I have now sourced every component BAR TWO for all my raw PCBs, using UK suppliers (without a £12 P&P charge).
So, it's time to ask for more help again.

The 2 parts, both off the stepper motor driver v2.3, are:

7805DT linear voltage regulator, Mouser part [http://gb.mouser.com/search/ProductDetail.aspx?R=863-MC7805CDTRKG] for which there are hundreds of options in Farnell, and I do not know which one is the right substitute

and 0.25 ohm 2W resistor type 2512, tolerance 1%, Mouser part [http://gb.mouser.com/search/ProductDetail.aspx?R=66-LR2512LF-01-R250] for which I cannot find another at 0.25 ohm at 2W.

Please can you tell me what are the most important features of these two items, or even better, suggest replacements?


Thanks again,
Hazel.

I think I've found the voltage regulator this morning (I had tried to put the post up about my progress last night - UK time - but the forum went down);
will this be the right item:
[http://uk.farnell.com/national-semiconductor/lp8340cdt-5-0/v-reg-ldo-1a-5-0v-8340-to-252-3/dp/9493344], or is the temp range too low?

In which case, will this one do?
[http://uk.farnell.com/stmicroelectronics/l4941bdt/v-reg-ldo-5-0v-smd-4941-dpak-3/dp/1087085] although it doesn't SAY positive.... is it?

oh and can someone remind me how to turn the path into a proper weblink?

Thanks,
Hazel.

The exact match for the 7805 is 1652337. The resistor is 1107452.

That said, Farnell has quite a lousy search system - most of the time, different parts with the same characteristics are described in different units or using different terms for the same thing. There were three spelling versions of the DPAK package for the 7805, and the sub-ohm resistors were displayed as 250mohm, that is, 250 miliohms - megaohms are Mohm.

YOU'RE MY MORNING STAR! Thank you so much.
I had tried 250mohms and well, every combination I could think of! And on some of my other hunts I'd realised their search didn't bring up everything, so I'd also gone through Google, but either way I'd not come up with these. I don't know how you did it, but thank you very much.

Do you know of a better option for the 4 pin molex header assembly/connector, polarised, Molex part 15244745 - it has a lead time of 2 months....?

Hazel

Ah, this one - your typical PC HDD power connector socket. It's damn difficult to get hold of everywhere.

Do you plan on using a PC power supply? If not, or you don't mind cutting the molex plugs off or rigging some "adapter" wires into the plugs, you can use a plain screw terminal. Any screw terminal with lead pitch (distance between pins) of 0.200" (5.08mm) will do, such as 1712805.

How about this one from Rapid Online, the part number 222920?
[http://www.rapidonline.com/Cables-Connectors/Connectors-Multipole/PCB-Interconnect/Disk-drive-power-connectors/63800/kw/power+connector]

Otherwise, I'll have to look into your suggestion.
Cheers.

Yes, that's what you need. If you don't mind paying some more postage, go for it.

Thank you for confirming that.

Some of my other components are from RapidOnline, too. The postage for them, plus the postage for LOTS of Farnell parts (meaning higher subtotal and therefore lower postage costs from Farnell) come to less than the £12 fee from Mouser.
I've also got ~4 parts from Maplin, which I can collect, and ~two parts from RS, which I can also collect, because one of their depots is local to me.

I'm going to put the full parts lists on my blog.
Hazel.

Hi Hazel

Both of the Farnell 7805 type V regulators you listed seem to only have a maximum input Voltage of 10v max in the Gen3 stepper board they could be supplied any thing from 12V > 50V

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Hi,
Courtesy of Enleth, I've settled on the Farnell 1652337, which has an input voltage of 20V, for the 7805DT.
I am constantly pleased and, yes, still, surprised by the level of interest and help I receive from the forum members. Thank you for your input. As I say, I knew nothing about electronics prior to starting this, and it has only become feasible in my eyes because of all the support I'm receiving. I'd never have dared otherwise!
Cheers,
Hazel.