Hi everyone, so I've been looking at some diy H-Bridge circuits and have noticed something common among most of them. Here's one example:
So as you can see this circuit is designed to work with arduino 5V, however, I think I might see a problem.
In order to switch the P-Channel mosfets with arduino, 5V npn transistors are used to control 12v and 0V at the P-channel gate. However the N-Channel mosfet is just getting 5V or 0V at the gate. If I'm not mistaken, most mosfets are only just on at the threshold voltage. So doesn't this mean that you end up with "well on" P-Channel mosfets and "only just on" N-Channel mosfets, which I assume would lead to some problems? I know there are logic level mosfets that can operate fairly well at 5V but would this difference in voltage still cause problems?
If so does that mean you need 2 more npn transistors to supply 12V for the N-Channels?
Also hopefully someone can confirm whether I'm right with this but the R(ds)on of a mosfet varies slightly dependant on the current(Id, what is the d referencing?) and Vgs