The 1st and 2nd order differential equations can be solved with Euler's equation (phasors) and calculus. This solution technique is compared with Laplace transforms. The course builds on Kirchhoff's laws to write differential equations using transfer functions. The particular solution reduces to a final condition if sources are replaced with a unit step function. All that needs to be calculated is the homogeneous step response. Then response to any complex voltage or current source can then be found through the convolution integral.