Author: Andrey Albershteyn Date: 28.07.19 Status: Good Enough Tags: feature, circuit-power-off
How to power off the whole device? With switch, relay or something else?
[28.07.19]
I want to completely power off the circuit as I assume it more safe. No current no problems. The following factors play role:
* Humidity can create short circuit
* High environment temperature + overheat on the output terminal
* Low quality of Chinese components
* Bug in the software (not fully disable led strip)
* etc????
[28.07.19]
I find a few way how to power off the circuit:
* Switch
* Relay
* MOSFET
Switch - very simple and cheap solution. However, the current in the circuit is 5A. Therefore, I need some reliable high current switch. Unfortunately, all of them are quite big for such a small device.
Relay - small, cheap, in combination with a small switch will give the same functionality. The disadvantage is the cwak noise.
MOSFET - requires radiator which quite big.
[29.07.19]
According to this 1 using relay we get unwanted electromagnetic radiation which is can be a problem for Bluetooth. I don't think it will broke it completely but can decrease distance and quality of signal. The most of the advantages of the relay doesn't suite for this application (such as AC switching, isolation, robustness)
Mosfet is small and cheap and looks like it can be used as a switch. So, I don't see why not use for this project.
I decided to you P-MOSFET. AOD4185L MOSFET P Trench 40V 40A 3V @ 250uA 15 mΩ @ 20A,10V TO-252-2(DPAK) RoHS
Proof that it is used as reverse polarity 2