# Lesson 9 — Transformers and Power Transmission

<p class="block-synopsis">Why transmission runs at high voltage, the turns ratio, and line losses.</p>

**Objectives covered**

- **1.6** — I can use a transformer's turns ratio, input voltages and currents, and output voltages and currents to calculate the efficiency, source voltage, and current of a power transmission system with one or more transformers.

<div class="block-toc">
  <a class="bt-card bt-reading" href="../Block1Reading/Obj06/ECE215_Obj06_Reading.html">
    <span class="bt-kind">Reading</span>
    <h4>Transformers and Power Transmission</h4>
    <p>The course reading for Objective 1.6.</p>
  </a>
  <a class="bt-card bt-flashcards" href="L09_Flashcards.html">
    <span class="bt-kind">Flashcards</span>
    <h4>Review deck</h4>
    <p>Key terms, equations, and ideas from this lesson, in a self-test deck.</p>
  </a>
  <a class="bt-card bt-slides" href="../_static/slides/ECE_215_Lesson09.pdf">
    <span class="bt-kind">Slides</span>
    <h4>Lesson 9 deck</h4>
    <p>The slides used in class, as a PDF.</p>
  </a>
  <a class="bt-card bt-practice" href="../downloads.html">
    <span class="bt-kind">Practice Problems</span>
    <h4>Work these before the quiz</h4>
    <p>Ungraded problems with answers, on the downloads page.</p>
  </a>
</div>