A vehicle heater control apparatus variably controls electric power to be supplied to a heater with an inexpensive configuration and simple control. The transmission path includes a waveguide assembly that includes a first minor face corresponding to the fixed port, a first major face that includes a recess extending from the first minor surface towards the fixed port. The interactive software application interfaces with a spreadsheet application to import data and formulas, and output interactive animated charts, graphs, and engineering solutions to simple and complex engineering problems.