why my transfomer is heating too much
I have made a power supply for a ckt which requires 200ma of current and my transformer is 9Vac at 500mA.
and then i have used a bridge rectifier and a 2200uf capacitor and after capacitor i have used LM317 as i need 5.1V at 200mA.
But my transformer and small heatsink of lm317 as getting hot
so what is solution to reduce heat
my ckt remains on for 24hours daily.
Is this heating obivious and i should ignore it
I have feel it with my hand.
The transformer is becomming hot and even the the regulator ic.
it is not so hot that it will burn you but still it is unbearable.
As I replied in your other posting, something is wrong in the wiring of your circuit, most probably the bridge rectifier. I have a similar LM317-based PSU operating continuously with very little heat anywhere.
no it does not get hot without load it only become hot with load
i am drawing 150mA in off state of switch and 200mA in on state of switch
50mA is used in making relay on.
this may be the reason
"U must be knowing that in india the transfomer rated 500mA can give 250mA and then ouput falls or in other words loading starts"
It transforms the 120vac mains to dc voltage specified by transformer. C1 and C2 would be about .1 uf, the diodes just standard silicon or rectifier diodes, the inductors about 1000 to 10000 uH. You could add a series resistor to limit current.
It transforms the 120vac mains to dc voltage specified by transformer. C1 and C2 would be about .1 uf, the diodes just standard silicon or rectifier diodes, the inductors about 1000 to 10000 uH. You could add a series resistor to limit current.
That circuit threw me for a minute. I've never seen one configured like that. Since capacitors do not pass DC, how can that work? Are c1, l1, for example, a filter? I'm afraid I don't understand.
Your transformer's voltage is too high for a 5.1VDC supply. No wonder the regulator gets warm.
9VAC makes a peak of 12.7V which is reduced to 11.2VDC by the bridge rectifier. Therefore the LM317 has 11.2 - 5.1= 6.1V across it and 0.2A through it which is 1.22W of heat.
The LM317 needs a min of about 3V across it for it to regulate very well.
If your transformer gets hot at less than half it max current rating then its quality is crap.
That circuit threw me for a minute. I've never seen one configured like that. Since capacitors do not pass DC, how can that work? Are c1, l1, for example, a filter? I'm afraid I don't understand.
I made a mistake, trere should have been only one capacitor across the output leads, the inductors are correct, they are to smooth the ripple voltage from the capacitor.
I would use a well-made Hammond 12.6VAC center-tapped 500mA transformer, two rectifiers and a main filter capacitor to give an unregulated voltage of 8.1VDC. Then the 5.1V regulator at 200mA would regulate perfectly and heat with only 0.6W and the transformer would barely get warm.
I made a mistake, trere should have been only one capacitor across the output leads, the inductors are correct, they are to smooth the ripple voltage from the capacitor.
At 50/60Hz the inductors would need to be huge to do anything, so it's extremely rare to have inductors like that. Where you do get them is in switch-mode supplies, where the high frequency used makes them worthwhile.