STDP MOSFET switch

Can anyone out there help me with a diagram for building a simple STDP Mosfet
switch?

What current and voltage are you trying to switch and at what frequency?

voltage current

Thanks for the reply,
I have 12v at 6amps continuous.I have a TEM that I would like to control to cool and heat. I have a two channel controller channel one is 14v @.2ma and channel two is a relay. 12v external power supply. I was using a IRF540NBF MOSFET to control the neutral side of the 12v power supply but I need to also isolate the +12 side.