The transformer works as expected without the bridge connected. The current draw anly happens when the bridge is connected son probably no short in transformer.

Reconnect the shield to the chassis with all secondaries still floating. If the shield is shorted internally to something on the primary side, this might indicate that.

ak

 

Yes this is the schematic.

Are you sure the bridge rectifier is wired correctly , you may have it across the +\- terminals ?? Post a picture of the rectifier.

 

I pulled the datasheet for your diodes, and you're using the wrong diode. Reverse current max, for this diode is 50uA.

No really i checked it many many times. Transformer outs to anode cathode junctions. Outputs are anode anode junction
(to use as load ground) cathode cathode junction for the positive side. I dosen't make sense to me also that is why i suggested that i make a video. I will do that, i will be home in 45 minutes or so.

I'm not saying that you aren't seeing the problem, I'm saying that it isn't wired as you suggest-- it cannot be. It is physically impossible for there to be any significant current on the 9.4VAC secondary if the circuit is open as shown below:

We look forward to your video

 

"Maximum reverse current = IR, the amount of current through the diode in reverse-bias operation, with the maximum rated inverse voltage applied (VDC). Sometimes referred to as leakage current. Ideally, this figure would be zero, as a perfect diode would block all current when reverse-biased. In reality, it is very small compared to the maximum forward current."
50uA seems small enough for me what would you suggest? By the way i think even 1n4007 is suitable for this operation. I just dont want to burn them that is why i test with larger Amp diodes. I will take the video in 15 mins.

 

Videos are ready! Sorry for my clumsiness trying to connect the bridge with crocodile connectors you should jump that part.
I was a bit excited it is my first video in the internet that i talk

The password for these two videos are : aac

In the first video i measure the mains power (i couldn't make contact with the probe leads properly but i think it is enough info) and the transformer secondaries.

Second video is about the bridge current problem diode testing etc.

 

You have constructed a direct short across one of the diodes.

Maybe even the other three, but my eyes are bad, so I can't see the polarity.

 

You have constructed a direct short across one of the diodes.

How where? Please give details.

 

You have the bridge wired wrong. The way it is wired there is a diode directly in shunt to the secondary and will present a short during half the cycle. The power in should be at diagonal corners, and the output should be on the other diagonal corners. Look again at the schematic and your wiring.

 

You have the bridge wired wrong. The way it is wired there is a diode directly in shunt to the secondary and will present a short during half the cycle. The power in should be at diagonal corners, and the output should be on the other diagonal corners. Look again at the schematic and your wiring.

I am now posting the close up of my wiring, it is exactly like the schematic. Maybe you can not see properly in the video, look at the junctions.
The green and black crocodiles are going to the transformer secondary.
The others are the outputs.
Do you still think it is wrong?
https://ibb.co/m2m3Ym

 

Thank you for the video, it's great.

In the video your problem is that you are connecting the positive lead off the transformer on one side of a diode, and then you are connecting the negative side of the supply on the other side of the same diode. You must drop your potential across 2 diodes, not 1. See my drawing in my previous post, for correct way to do this.

 

Ah ok! Maybe i understood the whole thing wrong, i was always attentive about junctions but not in this point of view. I will try and give feedback right away.

 

Ah ok! Maybe i understood the whole thing wrong, i was always attentive about junctions but not in this point of view. I will try and give feedback right away.

No problem. We all have done this. Sometimes, what the mind wants to see, and what's going on a two different things. I find myself obsessing over a schematic and a PCB when I'm about to get PCBs made for this same reason. Does the schematic work? Does the PCB actually match the schematic.

 

Yes! Yes! It such a fool of me you were right from the start. Yiili and Electricspidey also. I always looked to the junctions but never looked if that current is crossing from the same diode or not. Thank you for being such a helpfull and responsive comuinity. Now the circuit works as expected! Also this is not the first time i do rectification with a bridge ahh such a simple mistake!! angry to me ))
Very happy

 

 

View attachment 144779

just to be completely accurate this is what i did, which was wrong.

Transformer --> C---- A ---> Out
_______________A_____A
______________|______|
Transformer -->CA--CC ---> Out

The below picture you have shared is right.

 

just to be completely accurate this is what i did, which was wrong.

Is it correct (wrong connections)?

 

Is it correct (wrong connections)?
View attachment 144781

Yes this was the way i did it which was causing the problem.

 

Yes this was the way thet i did it which was causing the problem.

Usually, when I need to create bridge by fast way, I do it so:

 

Usually, when I need to create bridge by fast way, I do it so:
View attachment 144789

Thank you a good idea! This is much easier with crocodiles