IRF840 Mosfet Transistor TO-220 (SH) Code: 29928430

The IRF840 is a highly popular N-Channel power MOSFET built for high-voltage, high-speed switching applications. It handles up to 500V and 8A continuously, making it ideal for Switch-Mode Power Supplies (SMPS), motor drivers, and inverters.

Key Specifications

• Transistor Type:N-Channel Power MOSFET
• Drain-Source Voltage :Up to 500V
• Continuous Drain Current :8A
• Pulsed Drain Current :32A
• On-Resistance :85 Ω (maximum)
• Gate-Source Voltage :± 20V
• Gate Threshold Voltage :10V recommended (operates 2V–4V)
• Power Dissipation :125W
• Package Type:TO-220

Pin Configuration

The IRF840 features a standard 3-pin TO-220 through-hole package:

1. Gate:Controls the biasing of the MOSFET (requires 10V to fully turn ON)
2. Drain:Current flows in through the drain
3. Source:Current flows out through the source

Uses and Equivalents

It is commonly used in DC-DC converters, lighting ballasts, and audio amplifiers. If the IRF840 is unavailable, suitable replacements and equivalents include the IRF841, IRF843, STP8NA50, and 2SK1158. Because its gate requires a relatively high voltage to switch, it typically needs an external driver circuit to interface directly with low-voltage microcontrollers (like Arduino or Raspberry Pi).