The 840 from Goford Semiconductor is a MOSFET with Continous Drain Current 9 A, Drain Source Resistance 650 to 850 milliohm, Drain Source Breakdown Voltage 500 V, Gate Source Voltage -30 to 30 V, Gate Source Threshold Voltage 2 to 4 V. Tags: Through Hole. More details for 840 can be seen below.