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I begin in electronic, so sorry if my question is bad.

Can a LM2596 step-down converter accept 12V 8A as input ? I can read everywhere that the maximum output current is 2A or 3A but nothing about input current.

I have a 12V 8A DC Power supply to power a 5M 5050 LED strip (I know 3A is enough) and I want to power my Wemos D1 Mini Pro with 5V.

Scheme gonna be like this : enter image description here

Thanks for your answers.

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  • \$\begingroup\$ It's a step-down converter. That means the input current is less than or equal to the output current. \$\endgroup\$ – Hearth Jan 19 at 0:53
  • \$\begingroup\$ So what if I try with an 8A input? It will die ? \$\endgroup\$ – Hallia Jan 19 at 0:55
  • \$\begingroup\$ If there's 8A going in, that means there must be more than 8A coming out (or else something's gone wrong with the converter). Since this is only rated for 2A output, 8A input would be a fault condition. \$\endgroup\$ – Hearth Jan 19 at 1:01
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    \$\begingroup\$ Wait, if your question is "can I use this adapter" then the answer is yes. The 8A marked on the adapter is the maximum current, not a constant current it forces through things. \$\endgroup\$ – Hearth Jan 19 at 1:06
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    \$\begingroup\$ You're suffering from a common misunderstanding. Voltage sources are rated for the voltage they do give, and the current they can give. If you don't connect anything up to a voltage source, it will deliver no current. Each load will take as much current as it takes for that voltage -- but that's a property of the load, not the source. \$\endgroup\$ – TimWescott Jan 19 at 2:35
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You can use it so long as you take no more than 3A out of it. If you're buying one of these LM2596 modules online, taking more than 1.5A out of them tends to cause them to overheat and shut-down. enter image description here

It looks fine in your application, as it's only running the small logic module. I'm concerned about the MOSFET. if the LED strip wants several amps the current through it could overheat the solderless breadboard.

In that case run a wire directly from the 12V socket to the MOSFET and another from the MOSFET to the strip and a third from the strip to the socket so that the LED current does not flow through the fragile solderless breadboard.

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  • \$\begingroup\$ Thank you for your explaination! A will use a second power supply of 5V for my Wemos then. For the MUSFET thing I follow an adafruit tutoral for 5M LED strip. But for my project I will use 90 MOSFET to control 90 strip of 5CM. Do you see any problem with this ? \$\endgroup\$ – Hallia Jan 19 at 12:56
  • \$\begingroup\$ if there's a problem depends mostly on how much current the LED strip needs, and I can't tell that from only its length. I would treat currents greater than 1A as requiring soldered (or screwed etc) connections instead of breadboard. \$\endgroup\$ – Jasen Jan 19 at 20:41
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    \$\begingroup\$ @Jasen You're harsher on your breadboards than I; I would limit breadboarded connections to a few hundred mA maximum. I've had 1A-range currents melt cheap breadboards before. \$\endgroup\$ – Hearth Jan 20 at 0:37
  • \$\begingroup\$ The breadboard is just for prototyping. I will solder every component for the overall project. \$\endgroup\$ – Hallia Jan 20 at 13:48

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