Sender: <marv@lancaironline.net>
To:  lml
Date: Fri, 27 Nov 2009 08:40:07 -0500
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 receiver=logan.com; client-ip=75.180.132.121; envelope-from=dfs155@roadrunner.com
From: "Dan Schaefer" <dfs155@roadrunner.com>
Subject: Gear warning indicator
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Excuse me!! This looks to have at least two design faults.

Problem 1: If the airspeed switch is closed and any one (or more) of the 
green "down and locked" lights are energized via the gear position switches, 
12 volts will be applied thru one or more of the diodes to this "blinker" 
and it will try to operate - e.g., the 1000 mike capacitor will charge thru 
the 100 ohm resistor until the voltage reaches the relay pull-in voltage.

Problem 2: Unfortunately, as soon as the capacitor charges sufficiently to 
pull in the relay, the relay contacts close and the 12 volts is shorted 
directly to ground. Hopefully, only blowing a fuse or popping a breaker, but 
effectively taking at least the gear light circuit down.

Neat!

Dan Schaefer

PS: Stick the resistor on the other side of the relay contacts to at least 
solve the shorting - not sure what to do to keep this thing from blinking 
the lights when at least one gear leg is down and locked. But what do I 
know? I'm just a retired EE and things have a way of getting fuzzy in 10 
years!

DS 


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