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I have designed a circuit which powers up multiple components or electric modules from a source voltage of 12V. This circuit powers 1 micro controller (PSOC 5LP, rated voltage 12V), 3 stepper motors (rated voltage 12V, current 1A), 2 Servos (rated max voltage 6V), a laser module (rated 12V and required current of 2A) and a few LEDs and IR modules (rated voltage 5V). All these components are connected in a parallel network. The LED modules are supplied with regulated 5V from the source 12V. Now my question is, since all the components other than the laser require less than 2A of current, will supplying a maximum current of 2A and 12V form the source to this parallel network damage my circuitry and other components like the micro controllers or other LED modules?

Thank you so much, cheers

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  • \$\begingroup\$ The load takes what current it requires. If you supply a constant 12V you can't dictate the load current because the load is a resistor and obeys I = V/R. So a 10,000 amp supply at 12V connected to a 12 ohm resistor supplies only 1 amp. \$\endgroup\$ – Andy aka Sep 16 '15 at 17:52
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Your power supply must be able to suply the total currrent required by all loads. You list three steppers at 1 amp, and a laser at 2 amps, and other things with unspecified currents, so you need a power supply that can provide more than 5 Amps. How much more depends on the unspecified current requirements of the other devices.

If all devices are designed to operate from 12 volts, or are powered by suitable voltage regulators from 12 volts, each device will only draw the current it requires, as long as the supply can provide at least that current.

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  • \$\begingroup\$ Thanks bro. My power supply can supply up to 5A...i limited it to 1A because I worried about damaging the circuit...So I can just set it to 5A without damaging the circuit right? \$\endgroup\$ – Vino Sep 16 '15 at 18:00
  • \$\begingroup\$ As I said, you need a power supply capable of more than 5 amps, if all your devices are operated at the same time. \$\endgroup\$ – Peter Bennett Sep 16 '15 at 18:06
  • \$\begingroup\$ @VinokanthVelu you will also need to consider track width, separation and possibly heat dissipation if you are also designing a PCB. \$\endgroup\$ – BenG Sep 16 '15 at 19:28
  • \$\begingroup\$ @VinokanthVelu - You've got power supply amperage backwards. Saying that supply is rated for 5 amps doesn't mean that it will force 5 amps through the load (unless it's a current source - and yours is not. Trust me.) - it means the supply can provide 5 amps if needed. If you set the current limit too low, the supply will starve your loads and they won't work right. \$\endgroup\$ – WhatRoughBeast Sep 17 '15 at 1:16

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