Powering arduino nano and msp430 using two 7805's

I have two 7805’s using which i want to power up my msp430 and arduino nano.I have connected the inputs of 7805 to a 12v battery and outputs from both 7805’s are connected to msp 430 and arduino nano respectively.But for some reason one the 7805 connected to msp430 is getting heated up.Is there any harm in connecting the 7805’s in that way or there is any other better way to power up those two devices using a single 12v battery.I have attached a picture to show the way i have connected those devices using 7805.

With regards

One of the 7805 regulators seems to be wrongly connected to V-in of the Nano. V-in is the input of the onboard 5volt regulator. That pin should get 6-9volt, for the onboard regulator to make a stable 5volt supply. If you have 5volt, connect it to the 5volt pin.

The 7805 regulator for the Nano has to drop 12-5 = 7volt. That, and a current draw of ~35mA, will dissipate 7*0.035 = ~1/4watt in the regulator. That will raise it's temp ~15C above ambient (assuming there is nothing else connected/powered from the Nano).

Don't know the mps430. Post a link to the board. Leo..

The 7805 connected to the msp 430 is connected the wrong. If all the grounds are connected (as they should be) you have shorted the 7805 output by reversing the polarity to the 430

MarkDerbyshire: The 7805 connected to the msp 430 is connected the wrong. If all the grounds are connected (as they should be) you have shorted the 7805 output by reversing the polarity to the 430

In the circuit diagram i have drawn it wrongly but i have correctly connected on the board

I don't see batt ground connected to either Nano OR MSP, bottom 7805's 5V out is connected to MSP ground, 'taint right it is not correct. :)

outsider: I don't see batt ground connected to either Nano OR MSP, bottom 7805's 5V out is connected to MSP ground, 'taint right it is not correct. :)

Actually i have connected it properly on the board but i have posted the circuit diagram wrongly.

Hi, Welcome to the forum.

Please read the first post in any forum entitled how to use this forum. http://forum.arduino.cc/index.php/topic,148850.0.html

Can you please post a corrected copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

Can you post some pictures of your project so e can see you component layout?

Do you have a DMM?

Thanks.. Tom.. :)

I have posted the corrected picture and i have a multimeter

So you want to run the Nano on 4volt, not on 5volt?

Why two 7805 regulators. Is that msp430 a powerhog? Leo..

KARTHIK_HASYAGAR:
I have posted the corrected picture and i have a multimeter

No you haven’t, where does the lower 7805 get its input from?
P_20180328_174005 (5).jpg
Are any of the capacitors polarised?
If so please mark their polarity.

As asked previously why two LM7805s?

Tom… :slight_smile: