This circuit:

My circuit uses a 12v power supply, maximum supported current is 1A. Which MOSFET should I use to create a reversed polarity protection circuit? Can I use a CDSOT23-T15C-Q? Also is this circuit (image) fool proof?

 

Can I use a CDSOT23-T15C-Q?

No.
That's a diode array, not a MOSFET.
You can use any N-MOSFET with at least a 20V rating, and a low-enough on-resistance to not need a heat-sink when carrying 1A (≤0.1Ω.).

Also is this circuit (image) fool proof?

No, since nature always makes a better fool.
Define fool proof.

 

No.
That's a diode array, not a MOSFET.
You can use any N-MOSFET with at least a 20V rating, and a low-enough on-resistance to not need a heat-sink when carrying 1A (≤0.1Ω.).
No, since nature always makes a better fool.
Define fool proof.

Can I use a CDSOT23-T24?

 

Can I use a CDSOT23-T24?

No.
Why do you keep showing transient suppressors instead of a MOSFET?

 

This Circuit will do what You want ...............
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If your device could work about 10V then the easy way is to use 4 diodes(or bridge rectifiers) for the bridge rectification and their V/I ≥ 50V/4A, and then the 4 diodes will protect the device.