Small Electronic Project

PerrinV2 · 09-04-2010 02:57PM #1

(Not sure if this if the right forum to be posting in but...)Hello all,I'm working on a small electronic circuit myself here ---->>>
http://www.elektor.com/magazines/2008/july-047-august/dtmf-controlled-home-appliance-switcher.531629.lynkx

Just wondering would anyone know the pin outputs of B1 and B2?
As in +,-,~ and ~ ????
Any help would be appreciated,things haven't gone well so far...

x in the city · 09-04-2010 08:53PM

that pcb is uselsss, send on a pdf of the pcb so someone can see it properly.

its a bridge rectifier i assume...?

so it should be easy enough to match up the polarity of the diodes.

FarmerGreen · 10-04-2010 08:05AM

Spec sheeet for the bridge rec
http://www.wontop.com/pdf/BC1500.pdf
The + pin is longer, its at the top when the writing is horizontal, and its marked with a +.

The B2 bridge +ve is connected to R2, so the + pins would be bottom left on both.

steifanc · 10-04-2010 09:11AM

the two squiggles " i cant find that key do i have one ??"

is the ac in , unpolarized ,

+ - is the dc out polarized

PerrinV2 · 10-04-2010 09:22PM

Just also I'm thinkin component T1:BD139 looking directly down on the board I think it placed pin 1 first,then pin 2 then pin 3

And also does it matter which way the boxheaders go in as long as pin 1 on the board and the pin1 on the boxheader match up?

FarmerGreen · 10-04-2010 10:39PM

BD139 datasheet http://www.datasheetcatalog.org/datasheet/fairchild/BD139.pdf
Looks like he used the wrong footprint for the device.
Looking at the PCB with the writing normal way round
Top hole - R3 - Collector
Mid hole - R4 - Base
Bottom hole - ?- Emitter

BD139 pinout is E C B from the left (metal tab at the back)

Middle pin - Top hole
Left pin - Bottom hole
Other pin - last hole

Headers, shortest pins go in the board, also, some of them have small
bumps on the board side to prevent moisture wicking between the pins.

PerrinV2 · 11-04-2010 02:47PM

That bd139 is gonna be a nightmare to put in now so....

FarmerGreen · 11-04-2010 04:48PM

Like this?

PerrinV2 · 11-04-2010 05:12PM

No I mean in the sense that with the wrong footprint on the board the pins are too big on the bd139 to fit into the holes.

FarmerGreen · 11-04-2010 05:30PM

Oh right, how about E to mid pin IC3, B to leg of R4, C to leg of R3
On the component side.

PerrinV2 · 11-04-2010 05:40PM

I don't think E will reach IC3,but does it have to go there? there's no track on the board sayin its connecting to anything

FarmerGreen · 11-04-2010 06:04PM

Its a double sided board and they are only showing you the component side tracking
There should be a track on the other side (track side), named 'GND' on the circuit diagram.

Small Electronic Project

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