Transformer burn out !

[pixnum]

Dear Friend,

As I am facing a typical problem that when I increase volumn of my sony walkman or portable mp3 player, my transformer get burn out as I am using DC power supply circuit. Transformer is step-down 6-0-6 with 600 ma. Diodes are IN4007. Resistance is 150 ohm/1 watt. Can you tell me how I will solve this problem ?

Thank you,

Have a good day !

 

[Nigel Goodwin]

Presumably your transformer is too small for the load requirements?. You don't mention what capacitance you're using?, and what has the resistor got to do with anything?.

Perhaps you might post the EXACT circuit you're using?.

 

[mvs sarma]

Dear Friend,

As I am facing a typical problem that when I increase volumn of my sony walkman or portable mp3 player, my transformer get burn out as I am using DC power supply circuit. Transformer is step-down 6-0-6 with 600 ma. Diodes are IN4007. Resistance is 150 ohm/1 watt. Can you tell me how I will solve this problem ?

Thank you,

Have a good day !

You have not indicated the mains voltage. it is possible when input high voltage is encountered the primary drws more current - core gets saturated and only primary will burn.

it is also possible that your adopter may have a built in thermal fuse. if so you may be able to replace it and the adopter can perhaps restore. we know of such cases especially with external Modem power supplies.

Sarma

 

[pixnum]

Capacitor are 1000ohm/25 watts and main voltage is 220 volts

 

[Hero999]

That doesn't make any sense, capacitors are measured in Farads not ohms.

Going by your posts it sounds like you don't know what you''re doing so it's no surprise the transformer is burning out.

Please post a schematic of how you've connected everything together.

 

[mvs sarma]

Capacitor are 1000ohm/25 watts and main voltage is 220 volts

Pixnum has not indicated the country where he had this issue.

Perhaps he meant 1000:mu:F/25V



Sarma

 

[pixnum]

Sorry friend, I have commited mistake by mentioning the wrong parameter of capacitor value. Capacitors were in micro Fared. Anyway do you tell me again how to solve my problem ? I am using the same circuit design of DC power supply which I had posted early in this forum.

 

[mvs sarma]

Sorry friend, I have commited mistake by mentioning the wrong parameter of capacitor value. Capacitors were in micro Fared. Anyway do you tell me again how to solve my problem ? I am using the same circuit design of DC power supply which I had posted early in this forum.

Hi Pixnum,
i saw your post the pins of 7805 are shown reverse? pin 1 is input
pin2 ground and
pin 3 should be output ( this is when you hold the IC facing you and leads downwards.
what ever you do an adopter can't just burn by increasing the volume of a walkman or mp3 player- unless you laded a poer amplifier at the unregulated DC and tried for 5 or 10 watt amplifiers?
that too with a transformer of 600mA capacity at 6-6. these trnformers are overspecified by the makers in India. - please indicate, what all you lave loaded on the power supply.if the time of failure is late night hours - i fear the mains voltage would have gone high!!

Sarma

 

[Hero999]

I am using the same circuit design of DC power supply which I had posted early in this forum.

Could you please provide a link to it?

It would have been even better if you had simply posted in the origional thread though.

 

[pixnum]

Here it is the link for Hero999:

https://www.electro-tech-online.com/threads/dc-power-supply-pcb.28140/?highlight=dc+power+supply

 

[Hero999]

That thread contained a lot of arguing, it's no wonder you're confused.

Which circuit did you build in the end?

Do you still require 3V? Please accept that a stable 3V supply with good regulation is not possible using an LM7805, if you want 3V then use an LM317.

EDIT:
Look at the datasheet for the LM386, you don't need a stable power supply, there's no need for a regulator, use your centre tapped 6V tranformer with two diodes and a 4700:mu:F capacitor.

 

[pixnum]

Dear Hero999,

I will use my own circuit with slight modification with your inputs and I am hopeful that it will solve my problem.

Thank you for your advice !