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heating problem in new power supply circuit.

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tapu

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heating problom in new power suply circuit.

Dear all,
I require to use both 12v for relay & 5v for digital circuit in my project.Theirefore i use 12v regulator.& for 5v supply i used 7805 regulator.as follow.
PS.JPG
but 7805 heating continously.how to solve this issue.please reply.
 

Re: heating problom in new power suply circuit.

Don't you have I/P and O/P filter capacitors ? Have you used a heatsink for the Regulator ?
 
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Re: heating problom in new power suply circuit.

Hi
I think input overloading the regulator.You need to add a proper heat sink
W = V x I
For a linear regulator Power total = Power in load + Power in regulator.
Regulator Vdrop = Vin - Vload
Here Vdrop in regulator = 12-5 = 7V. so here power = 7v x load current
due to this power its heating, also you may need to filter the input of 7805 use some capacitor at i/p of 7805
 
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Re: heating problom in new power suply circuit.

LM.png
Above is the best circuit for 7805,
Please check below points for overheating
1) Please check the terminal pins you connected is correct
2) Any short circuit on the 5v output (remove all connection from 5v output and see )
3) Calculate the required output power at 5v out (7805 will give maximum 1A )
4) Put heat sink on 7805 if the current is less than 0.95A
 
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Re: heating problom in new power suply circuit.

Heating continuously means does it getting over heated or heat reaches to constant temperature.

In first case there seems to be some issue in your circuit connection where the output voltage of 7805 is getting connected.
In second case you just need to place a heat sink over 7805 IC.
 
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