I have a hardware component that requires 5V and 300mA to work. The Arduino output current of the Pins is 50mA, to the best of my knowledge. Only 40mA for 5V Pins.
My idea was to use the 5V and 2A of a phone charger, and switch it on using a relay and one of the IO pins. The relay is designed for 230V usage. Not sure if that would even work.
I thought of using a transistor, which is capable to handle that kind of voltage and current (TIP120). However, I am not sure how to connect the circuit around it, as the Collector and Emitter would be connected to the 5V 2A from the phone charger, but the Base would be connected to the Arduino, without the same ground. Anyone have ideas to design this? Thanks.
| Ranking | Name | Answers |
|---|---|---|
| 1 | PCBWay Team | 15 |
| 2 | Malcolm Low | 4 |
| 3 | Engineer | 2 |
| 4 | Engineer | 1 |
| 5 | Engineer | 1 |
| 6 | RODNEY THAYER | 1 |
| 7 | Arno Sommer | 1 |
In this case, a MOSFET is not a good idea unless it is a P channel. Using an N channel would shift the remote device ground depending on the current. As far as the question is understood, the poster also needs some form of isolation so MOSFETs, in general, wont work.
A fair point you make... if isolation is needed, a different solution must be found. But my assumption is the poster just wanted to know how to switch a 300mA load. And at that level, either P- or N- channel will work just fine, although you'd obviously put them in different ends of the circuit... You posted elsewhere that it would be good if people explained their use cases more clearly. I so agree with that. Usually one has to just kinda guess what on earth people are trying to do with the things they propose, and I think sometimes that can be even a real safety issue.
Agreed. That is why I tell people to better explain what they want to achieve. Having little to no information on the subject can only yield partial answers or very broad advice which is often rather useless.
May want to add a pull-down resistor to the base (and be sure that you include the free-wheeling diode as @Pete Dudash suggests) but, why not power your Arduino from the same 2A supply?
Depends on what Carl is trying to achieve. I asked him for more information so that we can provide better answers. No reply yet, obviously.
That Design looks correct