Electronics Handbook/Circuits/RL Series

Series RL Circuit 100px Circuit Analysis Circuit Impedance In Polar Coordinate = R/_0 + ω L/_90 Z = |Z|/_θ = /_Tan-1 In Rectangular Coordinate Phase Angle of Difference Between Voltage and Current In RL series circuit, only L is the component that depends on frequency . There is no difference between voltage and current on R . There is an angle difference between voltage and current by 90 degree . When connect R and L in series , there is a difference in angle between voltage and current from 0 to 90 degree which can be expressed as a mathematic formula below Natural Response ln I = I = I = I = Time Constant RL τ = I = A {| class="wikitable" width=50% ! t !! I(t) !! % Io |- |0 || A = eC = Io || 100% |- | || .63 Io || 63% Io |- | || Io || |- | || Io || |- | || Io || |- | || .01 Io || 10% Io |- |} Current of the circuit is decreased exponentially with time . At time t = 0 I = Io . At time t = R/L I = 63% Io . At time t = 5 time time constant I = 10% Io I = A Summary In summary RL series circuit has a first order differential equation of current Which has one real root