How Much Lag?
If you know the ratio of the inductive reactance to the resistance (XL/R) in an RL circuit, then you can find the phase angle. Of course, you can also find the phase angle if...
Category: Inductive Reactance
Inductive Reactance
Current Lags Voltage
When an ac voltage is placed across an inductor and starts to increase (either positively or negatively) from zero, it takes a fraction of a cycle for the current to follow. Once the voltage...
Vectors in the RL Plane
Engineers sometimes represent points in the RL plane as vectors. Recall that a vector is a mathematical quantity that has a defined magnitude (length) and defined direction (orientation). Expressing a point in the RL...
Points in the RL Plane
Inductive reactance can be plotted along a half line, just as can resistance. In a circuit containing both resistance and inductance, the characteristics become two-dimensional. You can orient the resistance and reactance half lines...
Reactance and Frequency
Inductive reactance is one of two form of reactance. (The other form, called capacitive reactance, will be discussed in the next section.) Reactance in general is symbolized by the italic uppercase letter X. Inductive...
Coils and Alternating Current
An inductor connected across a source of ac. Suppose you change the voltage source, connected across the coil, from dc to ac (above figure). Imagine that you can vary the frequency of the ac,...
Coils and Direct Current
IN DC CIRCUITS, RESISTANCE CAN BE EXPRESSED AS A NUMBER RANGING FROM ZERO (REPRESENTING a perfect conductor) to extremely large values. Physicists call resistance a scalar quantity, because it can be expressed on a...