2N7000 N-Channel MOSFET
A small-signal MOSFET with a low-ish gate threshold voltage but datasheet on-resistance specified at 10V gate drive, meaning it only partially turns on from a 3.3V or 5V microcontroller pin — fine for LEDs and small relay coils, not for higher-current loads.
How this component works
An N-Channel MOSFET is a voltage-controlled semiconductor switch, making it fundamentally different from current-controlled bipolar transistors (like the NPN). To turn a MOSFET on, you simply apply a voltage to its Gate relative to its Source.
Because the Gate is electrically isolated from the rest of the transistor by a microscopic layer of glass (silicon dioxide), it draws virtually zero continuous current. This makes MOSFETs incredibly easy to drive directly from microcontrollers. Once turned fully on, the path between Drain and Source acts like a very low-value resistor (Rds_on), allowing them to switch massive currents (often 10A to 50A) with minimal heat.
They are the backbone of modern power electronics, dominating motor drivers, 3D printer heated beds, and high-speed switching power supplies.
Deep Dive: 2N7000 MOSFET
Whether a MOSFET is safely usable straight off a microcontroller pin comes down to more than its threshold voltage. The 2N7000's threshold (Vgs(th)) is typically around 2.1V — comfortably below a 3.3V or 5V logic level, so the channel does begin conducting at those drive voltages. But its headline on-resistance figure is measured on the datasheet at Vgs = 10V, a gate voltage no microcontroller pin supplies. Driven at 5V instead, the channel is only partially enhanced, leaving RDS(on) considerably higher than the datasheet's specified value — for a small load like an LED (tens of mA) that extra resistance is irrelevant, but it makes the part a poor, inefficient, and potentially overheating choice for anything pulling meaningfully more current.
This is exactly the distinction the IRLZ44N in this category is designed around: that part's datasheet specifies RDS(on) at Vgs = 5V specifically, which is the actual engineering definition of a 'logic-level' MOSFET, not merely 'has a low threshold voltage.' The 2N7000, with its 10V-referenced spec and 200mA current ceiling, is correctly used for small-signal switching (LEDs, small relay coils, opto-isolators) where its partial-drive behavior at 5V is a non-issue — reaching for it to switch a motor or power LED strip directly from a microcontroller pin is the common mistake that a true logic-level part like the IRLZ44N avoids.
Common Use Cases
- Switching an LED or small indicator load directly from a microcontroller GPIO pin
- Low-current signal-level switching, such as toggling a small relay coil under ~200mA
- Level-shifting or simple logic-gate replacement in low-current signal circuits
Frequently Asked Questions
Can a 2N7000 be driven directly from a 3.3V or 5V microcontroller pin?
It will turn on to some degree — its threshold voltage (typically ~2.1V) is below both rails — but its datasheet on-resistance is specified at Vgs = 10V, so at 3.3V or 5V gate drive it does not reach that low-resistance state, leaving meaningfully higher RDS(on) than the datasheet's headline number. That is acceptable for small loads like LEDs but not for anything current-hungry.
Is the 2N7000 a "logic-level" MOSFET?
Not in the strict sense used by parts like the IRLZ44N in this category. A low threshold voltage alone does not make a part logic-level — the defining spec is where RDS(on) is measured, and the 2N7000's is measured at 10V, not 5V, so it under-performs its full potential when driven directly from typical microcontroller logic levels.
What is the 2N7000 good for, if not high-current switching?
Its low current rating (~200mA) and small TO-92 package suit it well to switching LEDs, small opto-isolators, or low-current relay coils, and to simple analog switch or level-shifting duties in signal-level circuits — anywhere the load current stays well under its 200mA ceiling.
Comparison Notes
Unlike the IRLZ44N in this category, the 2N7000's on-resistance spec is measured at Vgs = 10V rather than 5V, so it never fully turns on from typical microcontroller gate-drive voltages — it is a small-signal part, not a true logic-level power MOSFET.