Hello, for arduino what would be the best way of switching on and off 12v 15a?
I have a computer that is 300w power supply it is 12v coming into the computer and the rest is internal. I just wanted to be a way to switch it off and on remote if I need to using an arduino.
I was looking at one of these big solid state relays however I have been seeing stories how this catch on fire because most of them are fakes knock offs. I was looking at a power transistors and most of them I found are max at 8 to 10 amps. This computer fully running at max takes 286 watts.
That is quite a good P Channel mosfet with an RDS(on) of 0.0042 ohms.
At 25 amps, the heating effect will be about 2.5 watts so will require a heat sink.
To make that into a high side switch, you need only one NPN transistor and 2 resistors
Hello. Just an update. I was wondering something. Say If the highside mosfet is tiggered on and 12v is on. But say if I need to update new code. What do I do to keep the current state if it's already on so It doesn't turn it off then back on?
During update all MCU pins become inputs. With pullup/dn resistors you can force the pins into the desired (default) state.
Or you run all sensitive output signals through port extenders or shift registers which hold their last state while the MCU is busy with other tasks. An emergency alarm may reset all these chips so that a LOW signal should be the safe (OFF) state of all connected machinery.
