lets say I have 10 actors which I want to control with Arduino pins. Easiest would be to control them directly with the Arduino 5 V of the pins. But what if I do not have enough Ampere from Arduino? Can I add 5 V (for example through an additional supply + 7805) to the same circuit or would this damage something? The only other way I could think of, would be to use Mosfets. But this would be much more complicated because I would need a Mosfet for every single actor to my understanding.
timmorn:
lets say I have 10 actors which I want to control with Arduino pins. Easiest would be to control them directly with the Arduino 5 V of the pins. But what if I do not have enough Ampere from Arduino? Can I add 5 V (for example through an additional supply + 7805) to the same circuit or would this damage something? The only other way I could think of, would be to use Mosfets. But this would be much more complicated because I would need a Mosfet for every single actor to my understanding.
The max. current you should attempt to draw through a pin is not predicated on the supply's current rating - with a 100A supply you couldn't get 100A out.
It's possible that one FET could run all 10 "actors", unless the "actors" are supposed to act independent of each other. You wouldn't necessarily have to use FETs, junction transistors can honk lots of current. How much current does an "actor" draw, anyway?
How much current do these "actors" draw? Each pin of the arduino can handle up to 40mA with 200mA total.
The 5v supply of the Arduino can handle more if required. If you are only looking for 20mA for each, you can drive them from the outputs if you do not want all on at once.
If you need more than 20mA, you will need to look at transistors to drive them.
Can your actors work from low side switching (turn on/off by disconnecting from ground, commonly used for motors & LEDs)? Then an easy way is to use a shift register with open drain outputs. Can use 2 and daisy chain them, update them with 3 pins from Arduino and SPI.transfer() for fast updates.
TPIC6B595 can sink 150mA on each of 8 outputs.
If you need high side switching (turn on/off by opening connection to 5V) then P-channel MOSFETs are good.