So in my project I need to have 3 outputs that has 5v ( with each at least 1,5A) and one output that has 9v, so I though what if I bring one 9v source voltage with like 5A and put 3 regulators 7805 so I will have a circuits like this : enter image description here

Note that the regulators are not in parallel as each will supply a part in my project, so I wonder if I may have any problem using this circuit? if so how can I solve my poblem.

  • \$\begingroup\$ Hi Müller, Thanks for your reply, may I ask you? \$\endgroup\$
    – A.kame
    Aug 1, 2018 at 23:45
  • \$\begingroup\$ each passing more than 1.5A ? You may run afoul of the internal shutdown due to over-temperature unless you provide considerable heat sink to each. \$\endgroup\$
    – glen_geek
    Aug 2, 2018 at 0:11
  • \$\begingroup\$ Yes for each I will use a heat sink, and the 1,5A is a peak value, I don't need it all the time just once per minute or maybe more. \$\endgroup\$
    – A.kame
    Aug 2, 2018 at 0:14
  • \$\begingroup\$ How much total max current you draw from you 9V + 3x 5V? \$\endgroup\$
    – Jason Han
    Aug 2, 2018 at 2:15
  • \$\begingroup\$ about 5A peak (1,5A for each 5V and 500ma for the 9V) \$\endgroup\$
    – A.kame
    Aug 2, 2018 at 7:41

1 Answer 1


There is no inherent problem in using the same source for several regulators.

One aspect might require attention- if the individual parts of your project communicate with each other via logic signals, say, then if there is, say during power up or power down, more than a few hundred millivolts difference between the outputs then there could be issues. Using the same part types from the same supplier reduces the likelihood of that.

  • \$\begingroup\$ Ok, thank you very much for your reply, actually, the 9v goes for an arduino board+shield and the other 5v goes for servos,acutators, I use arduino's PWM to control them. \$\endgroup\$
    – A.kame
    Aug 2, 2018 at 0:00

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