I feel like a complete idiot. I'm a first year grad student and I still don't understand inductors. My question is about the sign of the voltage drop across an inductor.
Consider the gorgeous ascii art circuit below, where the C's are meant to be the inductor and the > indicates the direction of current.
Va --->---CCCCC------ Vb
Now everyone knows that the voltage drop across an inductor is
Va - Vb = L di/dt.
So according to this equation, if the current is increasing in the direction shown, the voltage drop (Va-Vb) will be positive. But I thought that an inductor was supposed to oppose a changing current. By that logic, when the current increases in the direction shown, shouldn't the inductor induce an opposite voltage (Vb > Va), in which case Va - Vb would be negative.
I'm sure there is a simple answer, but I've been pulling my hair out trying to resolve this.
Thanks,
-J
Consider the gorgeous ascii art circuit below, where the C's are meant to be the inductor and the > indicates the direction of current.
Va --->---CCCCC------ Vb
Now everyone knows that the voltage drop across an inductor is
Va - Vb = L di/dt.
So according to this equation, if the current is increasing in the direction shown, the voltage drop (Va-Vb) will be positive. But I thought that an inductor was supposed to oppose a changing current. By that logic, when the current increases in the direction shown, shouldn't the inductor induce an opposite voltage (Vb > Va), in which case Va - Vb would be negative.
I'm sure there is a simple answer, but I've been pulling my hair out trying to resolve this.
Thanks,
-J