SOLVED Unexplainable?!? (bad connections, my bad)

Please, i need your help to understand a little phenomenon...

I have created a board with a relay and i have a 5v power supply, the situation is:

If i connect the power supply directly to my board, it wont work, the relay won't trigger, but if i connect the power supply to the breadboard and from the breadboard to my board everything works just fine...
So why does that happens?!? is it some kind of miracle or what?

Thanks in advance

UPDATE: i only need to connect one of the wires to the breadboard, the other one can be connected directly

We need more information.
Where are you connecting this 5V power supply "directly" to your board. Is it through the power jack? If so you need about 7.5V to drive the regulator.

Grumpy_Mike:
We need more information.
Where are you connecting this 5V power supply “directly” to your board. Is it through the power jack? If so you need about 7.5V to drive the regulator.

the board doesn’t have a power jack, has 2 holes that i made, one 5V and the other GND…
you can see the board im talking about, on the schematic…

relay_board.brd (82.6 KB)

relay_board.sch (439 KB)

im not sure if those files were updated, heres the version im using…

the strange thing is that if i connect the power supply first to the breadboard, everything works… in my head that doesnt make sense

relay_board.brd (82.6 KB)

relay_board.sch (439 KB)

in my head that doesnt make sense

Not only in your head but on the page.
Any chance of a schematic that everyone can read?
However in this case a photo of the setup working successfully and one unsuccessfully might give more of a clue.

here are two pictures…

i have a webpage with a button… to turn the relay “on” and “off”, on one pictures everything works, on the other, nothing works…

hope to be clear enough :confused:

and btw, thanks for trying to help me

I can tell you that there is a 75% chance that there is anther problem preventing it from working! The other 25% would be that the wires do not have enough contact when you twisted them together. Try soldering them and see what happens!

using the connection from the non working version, if i use a led the leds turns on, so the power goest trough, i dont want to solder the power part in my board, because later i would have to unsolder when i put it on the definite place...

the twisted wires, are like 1 inche size twisted on the "breadboard" cables, so i dont believe that thats the problem... :S

what does a breadboard have that makes things work?

I don't see any power supply decoupling onthat board. Try soldering a 0.1uF ceramic cap under the board across the power rails. The bread board is possibly adding a bit of capacitance to the circuit.

Grumpy_Mike:
I don’t see any power supply decoupling onthat board. Try soldering a 0.1uF ceramic cap under the board across the power rails. The bread board is possibly adding a bit of capacitance to the circuit.

update, sometimes, it does work when connecting directly, like 1 out of 30, that sounds a good thing to try, though i would like to ask you to be more specific, cause im very new to all this stuff, and i just want to be sure what am i supposed to do instead of doing what i believe i understood…

is this what you mean?

UPDATE: not sure if important to tell, but the power supply im using is from and old cellphine charger

cap.jpg

i went searching online how to do it, and i tried using the 1uf cap without success, i used one of these 1MKP2-0.1uF/63V-5mm WIMA WIMA_ Metallized Polypropylene Film Cap.

Are you sure that there is not some other factor in play here? Check the voltage coming from the power supply. Is it consistent?

that question made to a beginner like me, i can only answer that, no, im not sure…
unfortunatly, i’ve lend my multimeter to a friend and he broke it :confused: but i’ve used 2 different power supplies (both old cellphone chargers) , and both work exacly the same…

i even tried a 47ohm resistor (the lowest i have here), just in case, but still not working…

if connected directly it only works when it feels like, it can take 10 tries or 50, but if connected to the breadboard it works 100 out of 100 so, taking common sense under consideration, i would say that the breadboard must have some magical components or something like that…

please tell me if i can do anything else for you, more experienced people, so it can be easier for you to identify the problem

Seriously guys, im not messing with you, but out of nothing it started working like a charm... i'm even affraid of touching it

I can only assume that it was bad connections on the holes of the board?!? i really can't explain but i would really like to say, for the record, THANK YOU VERY MUCH for all the time i made you guys waste on my problem, im sorry for that

No problem.

But if you have no decoupling caps on the board you still need them for stability and noise immunity. Yes connect them like you showed or better still directly across the pins of the chip with as short a wire lead as possible. A ceramic is much better than a tant, as it cuts out higher frequencies.