Electronic Circuit error

[endlessparadox]

Hello i have to build this circuit where you see the ~ icon it is the 2 input from a step down 14v transformer.When it is disconnected the transformer give 14v, when it is connected it gives only 4v there should be a defect in the circuit can someone help me find it please?

 

[davenn]

When it is disconnected the transformer give 14v, when it is connected it gives only 4v there should be a defect in the circuit can someone help me find it please?

1) what is the input to the transformer ?
2) if you are putting mains voltage onto a veroboard layout .... YOU SHOULDNT BE
3) doesn't look like you have cut the tracks between the primary and secondary terminals

At bre minimum, if you insist in putting mains voltage onto the board to the transformer primary terminals,
REMOVE ALL track areas under the red parts I have coloured in
CUT the board across the blue line



there could be other problems ... those are initially just the most obvious


please show a schematic for this project


Dave

 

[kellys_eye]

The OP states that 14V AC is put to the board at the points marked ~.

The lower ,~ point needs a break in the track as it connects to the LED (which it shouldn't). There may be other issues.....

 

[endlessparadox]

1) what is the input to the transformer ?

2) if you are putting mains voltage onto a veroboard layout .... YOU SHOULDNT BE

3) doesn't look like you have cut the tracks between the primary and secondary terminals



At bre minimum, if you insist in putting mains voltage onto the board to the transformer primary terminals,

REMOVE ALL track areas under the red parts I have coloured in

CUT the board across the blue line



View attachment 44000



there could be other problems ... those are initially just the most obvious





please show a schematic for this project





Dave

it is a step down 12 v transformer the ~ icon get the 12v from the secondary winding of the transformer which means transformer output there is a cross between the two input meaning i cutted the track there. I can remove the red tracks but it wont change anything because there is nothing there

 

[endlessparadox]

The OP states that 14V AC is put to the board at the points marked ~.

The lower ,~ point needs a break in the track as it connects to the LED (which it shouldn't). There may be other issues.....

There is a cross that separate the 2 ~ there is no zener only a 7812 voltage regulator with a capacitor and at the end a led to check if it is working or not.The circuit down i think doesnt matter for now because the power supply itself wont work

 

[kellys_eye]

Not the X between the two ~ symbols....... There should be a X below the lower ~symbol otherwise you're shorting that ~ point to the negative rail via the LED.

 

[hevans1944]

You need a "cross" (break in the Vero track) at D15. Or remove all of the trace between D15 and D20 to isolate the ~2 AC power lead from the LED/resistor circuit at D21 and D22.

 

[endlessparadox]

Not the X between the two ~ symbols....... There should be a X below the lower ~symbol otherwise you're shorting that ~ point to the negative rail via the LED.

You need a "cross" (break in the Vero track) at D15. Or remove all of the trace between D15 and D20 to isolate the ~2 AC power lead from the LED/resistor circuit at D21 and D22.

I moved the resistance one round lower same for the led so that there is no direct connection with the ac supply(~) but the transformer is still sending out 4v instead of the expected 14v there seems to be an error i checked all the diode capacitor etc... It is the 2nd time i made this circuit

 

[hevans1944]

How does moving the resistor and the LED "one round lower" change anything? There is still a direct connection from D11, D12, D13, and D14 downward to D15, D16, D17, D18, D19, D20, D21, D22, D23, D24, D25, ... , D46. You have essentially shorted your LED through the transformer and one of the rectifier diodes with no current limiting. Must be a pretty wimpy transformer not to have fried the LED by now.

Please draw up a schematic and post it here to allow us to compare it with your Vero-board layout, as @davenn requested in his post #2. We can't help you if you don't respond to our requests.

 

[endlessparadox]

How does moving the resistor and the LED "one round lower" change anything? There is still a direct connection from D11, D12, D13, and D14 downward to D15, D16, D17, D18, D19, D20, D21, D22, D23, D24, D25, ... , D46. You have essentially shorted your LED through the transformer and one of the rectifier diodes with no current limiting. Must be a pretty wimpy transformer not to have fried the LED by now.

Please draw up a schematic and post it here to allow us to compare it with your Vero-board layout, as @davenn requested in his post #2. We can't help you if you don't respond to our requests.

i moved the end resistor lead from d21 to e21 and d22 to e22 basically i i removed everything from the d track except the diodes and moved resistance lead and led lead to the e track
There is no schematic for the power supply just a bridge a 7812 voltage regulator a 1000 micro farad 50 v capacitor and a 1k ohm resistor followed by a common led
And basically here is the circuit
DONT pay attention to what i did with the pencil.

 

[AnalogKid]

A 7812 has three pins. There are six possible ways to connect them, and five of those are incorrect.

Please post a schematic with pin numbers so we can evaluate your circuit.

ak

 

[endlessparadox]

A 7812 has three pins. There are six possible ways to connect them, and five of those are incorrect.

Please post a schematic with pin numbers so we can evaluate your circuit.

ak

there is already watch the circuit there is 3 points with number 1,2 and 3

 

[kellys_eye]

there is already watch the circuit there is 3 points with number 1,2 and 3

How the heck were we supposed to know that?

Because you didn't have the track break at D15 (or 16, 17, 18etc) you've managed to connect AC to the output of the 7812. No wonder it doesn't work!

Show us your ACTUAL layout i.e. the soldered board.

Why don't you skip the transformer, rectifier, smoothing, regulator etc and just use a 12V wall wart? An awful lot safer than exposed AC mains on the transformer terminals, fewer parts and, most likely, working.

 

[endlessparadox]

How the heck were we supposed to know that?

Because you didn't have the track break at D15 (or 16, 17, 18etc) you've managed to connect AC to the output of the 7812. No wonder it doesn't work!

Show us your ACTUAL layout i.e. the soldered board.

Why don't you skip the transformer, rectifier, smoothing, regulator etc and just use a 12V wall wart? An awful lot safer than exposed AC mains on the transformer terminals, fewer parts and, most likely, working.

Red cables are ac

 

[davenn]

I can remove the red tracks but it wont change anything because there is nothing there

seriously
You asked for help .... I have told you a serious fault

ITS SHORTING OUT THE PRIMARY AND SECONDARY TERMINALS

is that clear enough !!

 

[(*steve*)]

Red cables are ac

The other side of the board would be good. That way we can see what you've actually done. Please don't use the flash on your camera.

 

[hevans1944]

This thread is going nowhere, possibly because of language differences, but also because of the naivety of the original poster:

the transformer is still sending out 4v instead of the expected 14v there seems to be an error i checked all the diode capacitor etc... It is the 2nd time i made this circuit

Gee whiz... second time you have made this circuit, eh? Did the first time not work either?

You did say in an earlier post:

When it is disconnected the transformer give 14v, when it is connected it gives only 4v

This is a strong clue that the transformer secondary winding is shorted or overloaded by something whenever you connect it. We have pointed out several problem areas. It is now your job to discover what you did wrong by using generally accepted troubleshooting techniques, such as a close visual comparison of your schematic against your as-built circuit board. The considered and intelligent use of continuity and resistance measurements is also a valuable troubleshooting tool when combined with a good understanding of how a circuit is supposed to operate.

It is beyond the scope of this forum to teach folks how to troubleshoot electronics, a skill that usually takes years of experience to develop. If you want to do "monkey see, monkey do" projects that is okay, but please make sure the "monkey do" part of the project accurately reflects the "monkey see" part.

 

[AnalogKid]

Please post a schematic with pin numbers so we can evaluate your circuit.

there is already

No, there isn't. The image in post #1 is not a schematic. It appears to be a wiring plan for a prototyping or perf board, but it is lacking a lot of information. It has two large and many small rectangles with no clue as to what any of them are, let alone their values.

Please post a schematic of *your* circuit.

ak

 

[endlessparadox]

No, there isn't. The image in post #1 is not a schematic. It appears to be a wiring plan for a prototyping or perf board, but it is lacking a lot of information. It has two large and many small rectangles with no clue as to what any of them are, let alone their values.





Please post a schematic of *your* circuit.



ak

im sorry if im annoying if you dont have the patience to help then just stop replying this thread i dont wanna beg but the only problem i got from this thread so far is the led problen which i fixed by moving to the e line in the breakboard.For the schematic i posted it in one of the comments high up.Im a beginner in circuits but even i find it obvious that the ic has 8 pins and the relay 5 pins i dont see how the circuit is causing problem because there are only led resistors one ic,relay,one voltage regulator.

These 2 pictures i uploaded are the only things i have.
And davenn point i simply dont understand it,he is telling me to cut a big red zone where there is nothing soldered there just an empty track what is the point? the relay 2 coil input and the output was separated in the middle if i didnt put it in the circuit.

I did the circuit and im having each time this 4v problem i suspect an error in the circuit.Another thing i didnt put a line from the ic pin 4 to negative or any line that bring the negative from the power supply down still no one found this problem it seems i corrected it.I only have a single question just fix the layout of the circuit.

And another thing im building on a veroboard

 

[endlessparadox]

The other side of the board would be good. That way we can see what you've actually done. Please don't use the flash on your camera.