While the MOSFET stays cool, the PTC will get hot during a fault—keep it away from heat-sensitive components like electrolytic caps. To help you select the specific components, tell me: Your input voltage range? The maximum current your device pulls?
The Gate is pulled low relative to the Source, allowing current to flow freely to the load. While the MOSFET stays cool, the PTC will
Provides simple, low-cost over-current protection. While the MOSFET stays cool
Always choose a PTC with a "Hold Current" slightly above your maximum expected operating current to avoid nuisance tripping. While the MOSFET stays cool, the PTC will
Unlike a standard diode that loses ~0.7V, a (e.g., AO3401 or IRF9540) has very low "on-resistance" (RDSon).
Protects the MOSFET Gate from high voltage spikes.