From b7cd6825c23c9365c8700c0e38b4d21b7b05366d Mon Sep 17 00:00:00 2001
From: ben-jaynes <1btjaynes@gmail.com>
Date: Fri, 26 Jun 2026 18:23:23 -0700
Subject: [PATCH] vault backup: 2026-06-26 18:23:23

---
 PCB Design/Music Player/Process.md | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/PCB Design/Music Player/Process.md b/PCB Design/Music Player/Process.md
index 2a2573d..0c41ace 100644
--- a/PCB Design/Music Player/Process.md	
+++ b/PCB Design/Music Player/Process.md	
@@ -43,4 +43,7 @@ Initially I was planning to use the [NHD-2.4-240320DA-CTXN](https://www.digikey.
 
 The display controller gives the option of using SPI or parallel RGB to control the display. I decided to go with SPI since it is much simpler to route and manage and I don't need the performance gained by the parallel RGB interface.
 ### Backlight Resistors
-To limit the current of the backlight for the display seri
\ No newline at end of file
+To limit the current of the backlight for the display series resistors are needed for the anode (power supply) pins. To calculate the value for the resistor the equation
+$$R = \frac{{V_{in} - V_{f}}}{I_{f}}$$
+is used which gives the current limiting resistor needed for a LED. The display used has a LED voltage of 3.0V and will be supplied with 3.3V. It also typically draws 160 mA of current. Plugging in these values gives
+$$R = \frac{{3.3 - 3.0}}{0.16} = 1.875 \Omega$$