(corrected) — Low Cost Reverse Polarity And Over Current Protection

Acts as the main switch for reverse polarity protection.

Provides simple, low-cost over-current protection.

If current exceeds the limit, the PTC heats up rapidly, its resistance spikes, and it effectively "opens" the circuit until the fault is removed and it cools down. 📐 Circuit Design Value/Part No. Q1 P-Channel MOSFET Reverse Polarity Switch F1 PTC Resettable Fuse Over-current Protection D1 10V - 15V Zener Gate Over-voltage Protection R1 10kΩ - 100kΩ Gate Pull-down 💡 Key Advantages Acts as the main switch for reverse polarity protection

The Gate is pulled low relative to the Source, allowing current to flow freely to the load.

Virtually zero heat generation compared to diodes. 📐 Circuit Design Value/Part No

Can be implemented in tiny SOT-23 or SOIC-8 packages for compact PCBs. ⚠️ Pro-Tips for Implementation Check Vgs: Ensure your MOSFET’s Gate-to-Source voltage ( VGScap V sub cap G cap S end-sub

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? Can be implemented in tiny SOT-23 or SOIC-8

All components are standard and cost pennies in bulk.