add a FAQ about the pyro on time

[web/altusmetrum] / FAQs / pyro_current.mdwn

diff --git a/FAQs/pyro_current.mdwn b/FAQs/pyro_current.mdwn
index 90b90c906898d5cd63af416decf623187582983b..361a7305d4757a31baa86e10803c59c9ba9730f1 100644 (file)
--- a/FAQs/pyro_current.mdwn
+++ b/FAQs/pyro_current.mdwn
@@ -3,7 +3,9 @@
 Older Altus Metrum products used Vishay Si7232DN FETs as switches.  They are 
 rated for 25A continuous, 40A pulsed.  Newer products use Taiwan Semiconductor
 TSM200N03D FETs which are rated for 20A continuous, 80A pulsed.  In pyro use, 
-we're closer to the pulsed rating than continuous.  However...
+we're closer to the pulsed rating than continuous.  
+
+However...
 
 Please note that Ohm's law applies.  Whatever your battery voltage is and
 whatever your e-match or other device's resistance are will limit the
@@ -22,7 +24,8 @@ conditions, which is why we think 50 milliseconds is .. a very long time!
 You'd think moving to a 9V alkaline would allow you to deliver 9A, but
 it doesn't really work that way.  Unlike LiPo batteries, Alkaline cells
 have a very high source resistance and their current producing ability
-is nowhere near linear. 
+is nowhere near linear. They work fine to fire commercial low-current 
+e-matches, but we strongly prefer LiPo batteries for our own projects.
 
 If you're using a programmable pyro channel on Altus Metrum products that 
 include that capability (TeleMega, EasyMega, EasyTimer) to do something like