# Understanding MOSFET ouput characteristics on a log-log scale

I am a second year BS Electrical Engineering student, and I am working on making an autonomous robot in my summer vacations, nowadays.

Right now I am designing an H-Bridge using discrete components for my robots' drive motors.

So, here's what I have done already.

After selecting the package of the MOSFET, and then finding the amount of power it can dissipate, given the operating temperatures, I was able to calculate the maximum allowed Rds(on) of the MOSFET to be selected. I then went on to select the right MOSFET i.e. IRF1010Z.

Now, when I went to look the output characteristics of this MOSFET in order to find the right gate voltage to apply to, so that Vds is low and that the MOSFET is able to conduct a maximum of 5A. However, the output characteristics of the device are given on a log-log scale that I don't seem to understand. The graph doesn't exist for low current values of (0-5A), which is the range I want to work on. So please help me understand the output characteristics of this MOSFET device. Here are the characteristics,

Maybe, a Vgs of 5-6 V will be fine, but what confuses me is the nonexistence of the graph for low current values.

• There are a lot of combinations for which the graphs do not exist, this isn't mean as an exhaustive chart. Try interpolating, or play it safe. Jun 16, 2016 at 10:53
• That's because that device isn't usually used for currents that piddly. Jun 16, 2016 at 10:53
• @PlasmaHH do you mean that I should use a Vgs of 10V or so? Jun 16, 2016 at 11:14