From 8be504601aeb9005b4e227fb2529d12672ea697e Mon Sep 17 00:00:00 2001
From: Sadeep Madurange <sadeep@asciimx.com>
Date: Tue, 13 Jan 2026 22:40:06 +0800
Subject: Tighten prose.

---
 _log/mosfet-switches.md | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

(limited to '_log/mosfet-switches.md')

diff --git a/_log/mosfet-switches.md b/_log/mosfet-switches.md
index 4fc1d31..bfe471a 100644
--- a/_log/mosfet-switches.md
+++ b/_log/mosfet-switches.md
@@ -4,9 +4,9 @@ date: 2025-06-22
 layout: post
 ---
 
-Needed low-power switching for the [fingerprint door
-lock](../fpm-door-lock-lp/). Servo and FPM draw high quiescent current--had to
-cut power electronically during sleep. MOSFETs can do this.
+Needed low-power switching for [fingerprint door lock](../fpm-door-lock-lp/).
+Servo and FPM draw high quiescent currents--had to cut power electronically
+during sleep. MOSFETs can do this.
 
 Schematics belong to <a
 href="https://electronics.stackexchange.com/users/292884/simon-fitch"
@@ -40,7 +40,7 @@ suitable through-hole MOSFET I could find.
 
 ![N-channel high-side switching circuit](n_high_side.png)
 
-Less common but works if you have voltage high enough to drive the gate. Both
+Less common but works if you have a voltage high enough to drive the gate. Both
 M1 and M2 are N-channel. MCU low → M2 off → M1 gate rises above threshold →
 servo on. MCU high → M2 on → M1 gate drops → servo off. R2 prevents
 high-impedance power-up from switching servo on.
@@ -49,7 +49,7 @@ M2 needed in both topologies for level conversion (0V ↔ +6V or +9V). Carries
 <1mA. Gate-source threshold must be lower than MCU supply. Common choices:
 2N7000, 2N7002, BSS138.
 
-Note: D1 flyback diodes protect MOSFETs from voltage spikes caused by inductive
+Note: D1 flyback diode protects MOSFET from voltage spikes caused by inductive
 loads (servos, relays).
 
 ## A BJT alternative
@@ -58,14 +58,14 @@ loads (servos, relays).
 
 Simpler, cheaper, more available. Q2 conducts when MCU outputs high. Q2
 amplifies Q1's base current. Unlike MOSFETs (voltage-driven), BJTs are
-current-driven. R3 and R4 must be calculated for desired base currents.  <a
+current-driven. R3 and R4 must be calculated for desired base currents. <a
 href="https://teachmetomake.wordpress.com/how-to-use-a-transistor-as-a-switch/"
 class="external" target="_blank" rel="noopener noreferrer">Guide on BJT
 switches</a>.
 
 ## Which topology?
 
-MOSFETs preferred in professional work—more efficient when on. Harder to drive
+MOSFETs preferred in professional work--more efficient when on. Harder to drive
 at 3.3V due to V<sub>GS</sub> requirements for full saturation (low
 R<sub>DS(on)</sub>).
 
@@ -73,7 +73,7 @@ N-channel: Lower on-resistance, cheaper, more efficient than P-channel. Harder
 to drive high-side (gate must be above source—requires extra circuitry like
 MOSFET drivers).
 
-Used P-channel high-side for the door lock redesign. Simpler to drive from 3.3V
+Used P-channel high-side for door lock redesign. Simpler to drive from 3.3V
 MCU, no driver needed.
 
 ## Further reading
-- 
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