From 1bf9a50a937c89a7cbf95fb81573127658da434c Mon Sep 17 00:00:00 2001
From: Alvie Rahman <alvierahman90@gmail.com>
Date: Sat, 18 Feb 2023 20:28:06 +0000
Subject: [PATCH] add power factor

---
 uni/mmme/2051_electromechanical_devices/ac_power.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/uni/mmme/2051_electromechanical_devices/ac_power.md b/uni/mmme/2051_electromechanical_devices/ac_power.md
index e77e5fc..13477d0 100755
--- a/uni/mmme/2051_electromechanical_devices/ac_power.md
+++ b/uni/mmme/2051_electromechanical_devices/ac_power.md
@@ -8,6 +8,8 @@ lecture_slides: [ ./lecture_slides/MMME2051EMD_Lecture3B.pdf ]
 exercise_sheets: [ ./exercise_sheets/Exercise Sheet 4 - Power factor and three phase.pdf ]
 ---
 
+This section builds on [introduction to AC](/permalink?uuid=0c90c691-cbf8-43e9-bfa5-7b277c853151).
+
 # Definitions
 
 - Phase voltage - voltage across any phase
@@ -49,3 +51,7 @@ $$I_\text{line} = I_\text{phase}$$
 $$|V_\text{line}| = |V_\text{phase}|$$
 
 $$I_\text{line} = \sqrt 3 I_\text{phase}$$
+
+# Power Factor (PF)
+
+$$\text{PF} = \cos{\gamma} = \cos{\left(\Phi_v-\Phi_i\right)}$$