Hi,
I am designing a Reverse polarity protection using P-mosfet for a wide input range 12V -60V. Could you please help me in choosing the value of resistance R6? I am using the zener diode ( ZPD15), with 5mA test current 500mW power dissipation.

 

It's been done many times.
Good luck.....

 

Could you please help me in choosing the value of resistance R6?

Why is that a problem?
So what would be the voltage across the resistor at 60V, and how much current do you want through the resistor (which is also the Zener current) at that voltage?
Use Ohm's law from there.

 

Why is that a problem?
So what would be the voltage across the resistor at 60V, and how much current do you want through the resistor (which is also the Zener current) at that voltage?
Use Ohm's law from there.

I already know it is a voltage divider circuit, but the problem here is: I have a wide input range from 12 to 60V, so which value of the voltage should be considered, for calculating the resistance value.