I'm using an Arduino to control a 12v water pump for a self-watering plant wall. I'd also like to use the same power supply for both, and probably need surge protection of some kind to avoid spikes. I would like to understand the pros and cons in general of various methods of switching power.
I've come across various methods of switch power on and off, but have little idea of the pros/cons for each. Here's the ones I know about:
- Use a transistor (usually a MOSFET) to switch power.
- Use an opticoupler to toggle power.
- Use a relay to control power output. The microcontroller usually doesn't have sufficient power to switch the relay. So you end up having to have an additional circuit which controls power to trigger the relay. This seems silly.
To me, it looks like an opticoupler would be the best option. There's no heat buildup from a transistor (I think), and there's no need to use power to trigger switching the power as in a relay. However, it's not the most common way of switching, and I don't understand why.
If this question is too vague, please do flag it, but also help me make it more concise. I might not know the terminology to ask a good question.