Hi there,
I am trying to control an LED with Vf = 6.25V, with an Arduino (5V logic).
My solution is to use an nMOS transistor to simply switch it on and off. However, I'm confused about whether or not I still need a current-limiting resistor for the LED, which I want to operate at 150 mA.
I know the equation for saturation current through an nMOS is Id = (K/2)(Vgs-Vt)^2, where K is a constant dependent on specific mosfet parameters. Thus, the mosfet doesn't act like an ideal switch (open/closed with zero resistance). So to get my desired 150 mA, should I just buy a MOSFET with 150mA Id for Vg = 5V?
Thanks
I am trying to control an LED with Vf = 6.25V, with an Arduino (5V logic).
My solution is to use an nMOS transistor to simply switch it on and off. However, I'm confused about whether or not I still need a current-limiting resistor for the LED, which I want to operate at 150 mA.
I know the equation for saturation current through an nMOS is Id = (K/2)(Vgs-Vt)^2, where K is a constant dependent on specific mosfet parameters. Thus, the mosfet doesn't act like an ideal switch (open/closed with zero resistance). So to get my desired 150 mA, should I just buy a MOSFET with 150mA Id for Vg = 5V?
Thanks