2N7000

The 2N7000 is a N-channel, enhancement-mode MOSFET used for small-signal switching applications.

Packaged in a TO92 enclosure, the 2N7000 is a 60 volt device capable of switching in the 200-350 milliamp range with an on-resistance of 0.3-5 ohms.

The main use of the 2N7000 is as a switch for low voltages and currents. In switching circuits, the 2N7000 can be used much like an NPN Transistor, but has advantages:
* low threshold voltage means no gate bias required
* high input impedance of the insulated gate means almost no gate current is required
* consequently no current-limiting resistor is required in the gate input

The main disadvantages of the 2N7000 over a bipolar transistor in switching are the following:
* susceptibility to cumulative damage from static discharge prior to installation
* circuits with external gate exposure require a protection gate resistor or other static discharge protection
* Non-zero ohmic response when driven to saturation, as compared to a constant junction voltage drop in a bipolar junction transistor

The circuit symbol for the 2N7000 generally does not show the internal Diode formed by the substrate connection source to drain.

External links

* [http://www.onsemi.com/pub/Collateral/2N7000-D.PDF Datasheet for On Semiconductor's 2N7000 (PDF)]
* [http://www.datasheetarchive.com/search.php?q=2n7000 2n7000 Photo]
* [http://wa5znu.org/2007/07/2n7000/n6kr-2n7000.txt Application Notes for Experimenters]
* [http://home.comcast.net/%7Ebotronics/efield.html E-Field Sensor] demonstrates extremely high gate impedance with a simple LED circuit
* [http://hades.mech.northwestern.edu/wiki/index.php/Driving_using_a_single_MOSFET Driving a single MOSFET] Detailed description of usage of a similar MOSFET