Yes if you disconnect the top of the 47k ohm resistor and wire it instead to an Arduino output pin, along with a common ground wire from the arduino to common ground from the 6 volt source, it should work in principle. Requiring less gate voltage for any given operation mode. Yes, however a logic level mosfet can be used for both linear and switching mode, just like a normal mosfet but Many recommend using such a series gate resistor to limit gate current, it doesn't matter which kind of mosfet.Ĭan you confirm what igor is saying about Logic Level? Both normal and logic level mosfets do not have internal series resistors. It works the sameĪs a normal mosfet, just with lower gate voltage values, making it easier to interface directly to 5vdc logic No, logic level mosfet is just a mosfet with a lower gate threshold and gate saturation voltage values. So you are saying Logic Level MOSFET is just a common MOSFET with the limiting resistor for gate inside? (google motor slow start if motor's start-up current exceeds the current rating of the MOSFET). Keep in mind some motors have very high start-up currents, so you may need to find a way to "slow start" it. Basically, the MOSFET will source as much current as the motor needs (which depends on the momentary resistance of the motor). The actual current through the MOSFET will depend on the needs of the motor (in your case). The current rating only tells you the maximum current the MOSFET can conduct without daamaging itself. The current flowing through the MOSFET has nothing to do with the current rating of the MOSFET. I don't know about logic level MOSFETs, but my guess is they work in cutoff and saturation region, skipping the linear region so they are either ON or OFF. So the transistor acts like a resistor controlled by Vgs. Vth - MOSFET threshold voltage (from datasheet) Yes if the MOSFET is in the linear region (Vgs > Vth) and (Vds < (Vgs-Vth)) where: The mosfet is in saturation and will allow as much current to flow as ohms law dictates, up to the heat dissipation rating of the mosfet. Not exactly, The maximum current rating of the Mosfet must be higher (X2 is not too much excess rating) then the maximum load current of the motor, but the motor and source power supply voltage determines the actual amount of current flow. Must see the gate voltage Vs current flow graphs in the specific mosfet datasheet to determine the current curve Vs gate Mosfets canīe operated in a linear manner as well as the more common switching manner as with most arduino application. Gate voltage can determine current flow if it's above threshold voltage, but below fully saturated gate voltage. ![]() Also a resistor, 10k ohms, between gate and source is a good safetyįeature in case motor voltage is still on, but arduino power is turned off, to ensure motor stops. Output pin to limit this charge/discharge gate current. Of the mosfet due to capacitance charge of the gate, so many recommend a 200-1k ohm series resistor between gate and ![]() Gate current occurs only at initial turn on and off Gate voltage determines source/drain current flow. Including other parameters to watch out for. Hopefully the god members will clarify this. If the Logic does fully turn on the path, so the amount of current flowing from source to drain depends on the current rating of the MOSFET? Say 14A, therefore 14A will flow (thereby one needs resistor )? Or depending on the needs of the motor?.Logic Level does not control the amount of current, but just turns fully ON and OFF the path?.One can control the current passing thru source to drain by controlling the voltage at the gate?.The basic idea I want to clarify is the difference, pros and cons between using common MOSFET as opposed to Logic Level MOSFET. So, using MOSFET is one effective way at this. Basically this is for switching motors on/off, not controlling the direction. I have been reading a lot about BJTs and FETs, MOSFETs, Logic Level MOSFETs. I just want to clarify this basic idea, of which I know nothing, and want the ones with the knowledge to share them.
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