Post the .... circuit otherwise you are just talking in circles.
What's powering the sensor heater? You can't have taken that into account in your measurement it's way bigger than 5mA.
I'd guess, and it can only be a guess without a circuit, that you have wired something up wrong, or you are measuring something incorrectly.

 

What is the output voltage of the 7805?

 

Have you measured the temperature of the device that you say is over heating. Information is powerful. Clear communication is imperative.

 

What is the output voltage of the 7805?

its 5 v sir

 

Have you measured the temperature of the device that you say is over heating. Information is powerful. Clear communication is imperative.

it can feel by touching sir, its too hot

 

is it because of the internal shortcircuit of the Alcohol sensor MQ-03...?
Because i found continuity in supply....

 

Some 7805's operate with a junction temperature of up to 125° C, others higher temperatures. If it gets too hot its internal protection circuit will shut it down. Is it shutting down?

 

Some 7805's operate with a junction temperature of up to 125° C, others higher temperatures. If it gets too hot its internal protection circuit will shut it down. Is it shutting down?

no

 

Still no schematic............

 

Hello,

Are you using the correct decoupling capacitors on the LM7805?

Without them the regulator might oscillate and get hot from it.

Bertus

 

If it is not shutting down you do not have a problem.

 

Hi,

I connected two dc fan with the circuit and used a 7805 and i found that its taking about 574 ma current, its found too heating, can i use any other dc regulator ( input of voltage upto 24v max)

 

The 7805 is designed to deliver one amp, so it is safe as far as current is concerned. If use a different regulator in the same IC package and the same circuit you will get the same temperature.

If you feel the need to reduce the temperature you might find one of these methods helpful:

The best solutions are to add a heatsink;

Reduce the voltage into the regular. This can often be done by putting a resistor in series with the regulator);

Reduce the current through the regulator. You can put a resistor between the regulator's input and output but be careful because the voltage could go all the way to 24V with no load. It is possible to prallel 7805 regulators but at the expense of regulation-this is analogous to getting a heatsink and it more difficult to do "right".

I think you don't have a way to measure temperature accurately, but if you don't have an appropriate thermometer you can always use the "spit test". Be quick and careful doing this: Wet the end of your finger or a cotton swab and touch it to the metal tab of the regulator. If you hear the water turn to steam, then it might be too hot (as discussed above if it really is too hot, it will shut itself down). If there is no hiss then it is not too hot.

 

What is the voltage on the INPUT pin of the 7805?

Can you post a photo of the 7805 + heatsink assembly?

ak

 

it can feel by touching sir, its too hot

If you didn't leave some skin behind, it is not too hot!

Spray some water on it; if the water doesn't boil, then it is not too hot...