# Lesson 22 — IR Emitters

<p class="block-synopsis">Every aircraft glows in the infrared, but not evenly and not always in the same band. This lesson breaks the signature into five components, ranks them with one intensity rule, and finds the twice-daily moment when the airframe vanishes into its background.</p>

<div class="block-toc">
  <a class="bt-card bt-reading" href="L22_IREmitters_Reading.html">
    <span class="bt-kind">Reading</span>
    <h4>IR Emitters</h4>
    <p>The five signature components, the in-band intensity ranking rule, aspect and look-geometry, and thermal crossover.</p>
  </a>
  <a class="bt-card bt-flashcards" href="L22_Flashcards.html">
    <span class="bt-kind">Flashcards</span>
    <h4>Review deck</h4>
    <p>Key terms and relations from the lesson, in a self-test deck.</p>
  </a>
  <a class="bt-card bt-preflight" href="L22_Preflight.html">
    <span class="bt-kind">Pre-flight</span>
    <h4>Pre-flight quiz</h4>
    <p>Five questions to work before class — anyone can be called to the board.</p>
  </a>
  <a class="bt-card bt-slides" href="../_static/slides/ECE%20495%20-%20EW%20and%20Survivability%20-%20B3L22%20-%20Fall%202026.pdf" target="_blank" rel="noopener">
    <span class="bt-kind">Slides</span>
    <h4>Lesson slides</h4>
    <p>The deck we work through in class, as a PDF you can annotate.</p>
  </a>
  <a class="bt-card bt-demo" href="L22_ThermalCrossover_Demo.html">
    <span class="bt-kind">Demo</span>
    <h4>Thermal Crossover</h4>
    <p>Run a diurnal model and watch the LWIR skin-vs-terrain contrast pass through zero about an hour after sunrise and sunset.</p>
  </a>
</div>
