Hawkins Electrical Guide v. 05 (of 10) / Questions, Answers, & Illustrations, A progressive course of study for engineers, electricians, students and those desiring to acquire a working knowledge of electricity and its applications

by N. Hawkins

Properties of Right Angle Triangles.—In order to understand the graphical method of solving alternating current problems, it is necessary to know why certain relations exist between the sides of a right angle triangle. For instance, in every right angle triangle:

The square of the hypothenuse is equal to the sum of the squares on the other two sides.

That is, condensing this statement into the form of an equation:

hypothenuse² = base² + altitude² (1)

the horizontal side being called the base and the vertical side, the altitude.

This may be called the equation of the right angle triangle.

Fig. 1,308.—Sine curves showing phase relation between current and reverse pressure of self-induction. This reverse pressure, being proportional to the rate of change in the current strength, is greatest when the current is at zero value, and zero when the current is maximum, and in phase is 90° behind the current.