what's the size .....and where are u now?
plus what is the transistor used ?

Send me the details.

 

what's the size

20.20 x 20.00 mm

.....and where are u now?

At the kitchen table, on the way to bed...

plus what is the transistor used ?

SOT-23 EBC footprint.

Send me the details.

Tomorrow...

 

Sigh !! good night.

 

Did a quick search:

Can we use this transistor?

BC817

{ed}
Just re-read post #12...

 

Did a quick search:

Can we use this transistor?

BC817

{ed}
Just re-read post #12...

Ya ..that will suffice if you can get it for me.

 

Ya ..that will suffice if you can get it for me.

Of course I'll get it. How many do you need?

 

The part no. says BC817-25...data says BC817 only.

Is there any difference , why the"-25"

 

It says something about that in the datasheet, page 3.

 

Oh ..Gain..Shoooot ! only missed that. Thanks.

So..Gimme a component list, since you all changed the types, I need an update and recheck my stock.

tell me, am I to put the resistors in the LED arrays. I means the low value 0.25W ones are off the board ?

 

No... Unless I made a mistake...

Check images in post #33.

Changed PADs on the sides back to through-hole. All LED resistors are on the right-hand side of the board.

Need to do an alignment on the R's, (so it looks neater), and move one R from under the uC closer to the NPN it's connected to.

I'm at work right now, and I will upload a part list, as soon as I get home.

 

Aaah ! thought so...

I might need the SMD R u guys changed and which I might not have right now.

 

I'll check the availability up against the partlist.

What quantities are we talking about?

 

First gimme the list with package type and all.
Then I'll go on a shopping spree!

 

R!f@@ if you want higher Total Device Dissipation. You must change the package from sot-23. However a sot-23 and the TO-92 package do have about the same footprint size. But the TO-92 have a Total Device Dissipation around 500mW. Jens and I use the same component pusher. I did a search and came up with the MPSA 06G transistor. It has about the same price as the sot-23 variants that has been suggested. But it has quite low VCE(sat)=0.25 volt max at IC 100 ma, and also IC max=500 mA. The hFE factor should also be good enough figure 10 in the datasheet
http://www.onsemi.com/pub_link/Collateral/MPSA05-D.PDF

 

Attached is what I have right now and will be using for this circuit.

I believe the transistor is over rated. but if the package won't change no need to change it, since max Ic will be 50mA.

Circuit will use 12V, 3 LED's in series per string.
Oh ****...Just remembered. I made a change in the original Meter at the last minute. U see there are 6 resistors. 2 per transistor.
You would think it would be for 2 strings and yes they are but not quite.

1 string has 3 LED's, and additional branch will power 1 LED, which means the R should increase.

I am calculating the needed resistor values. No worries on tht jens, cause the design and pads won't change, just the values of the resistance.

 

I believe the transistor is over rated. but if the package won't change no need to change it, since max Ic will be 50mA./QUOTE]
Then I suggest you go for the BC 817K-40 variant. As it has better hFE than the -25 variant. That makes it more versatile I guess

 

Transistor changing is up to Jens, if he can get it, then I have no problem.

Ones Jens lists the parts, I can give this a go for etching.
But before that I like to see the file. Print it and see it close up u know.

 

This is what I got, for now.

This weekend I'm quite busy. Still needs to align the R's and move one of them.

 

OK.
Changed to the BC817-40 SMD transistor.
Moved and aligned some R's

Is this "good to go?"

Size: 20.2 x 20.0mm

 

Removed some resistors...

Board size: 18.8 x 20.0mm
And made the PADS bigger.