X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from bay0-omc1-s23.bay0.hotmail.com ([65.54.246.95] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1222141 for flyrotary@lancaironline.net; Mon, 03 Jul 2006 10:40:42 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.54.246.95; envelope-from=lors01@msn.com Received: from hotmail.com ([65.54.250.80]) by bay0-omc1-s23.bay0.hotmail.com with Microsoft SMTPSVC(6.0.3790.1830); Mon, 3 Jul 2006 07:37:05 -0700 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Mon, 3 Jul 2006 07:37:05 -0700 Message-ID: Received: from 4.171.150.125 by BAY115-DAV8.phx.gbl with DAV; Mon, 03 Jul 2006 14:37:01 +0000 X-Originating-IP: [4.171.150.125] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: EM-2 question for Tracy Date: Mon, 3 Jul 2006 10:36:53 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0073_01C69E8C.99CE4500" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.20.0029.3000 Seal-Send-Time: Mon, 3 Jul 2006 10:36:53 -0400 X-OriginalArrivalTime: 03 Jul 2006 14:37:05.0459 (UTC) FILETIME=[27B94830:01C69EAE] Return-Path: lors01@msn.com This is a multi-part message in MIME format. ------=_NextPart_000_0073_01C69E8C.99CE4500 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageRusty got it right (as usual). I had incandescent lights in mind = when the circuit was designed but LEDs will work as long as the = limitations pointed out by Rusty are observed.=20 Tracy ----- Original Message -----=20 From: Bill Schertz=20 To: Rotary motors in aircraft=20 Sent: Sunday, July 02, 2006 11:15 PM Subject: [FlyRotary] Re: EM-2 question for Tracy Thanks Rusty, that describes the behavior exactly. 12V supply, 12V = prepackaged LED that glows dimly when power is applied to EM-2. Bill Schertz KIS Cruiser # 4045 ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Sunday, July 02, 2006 9:01 PM Subject: [FlyRotary] Re: EM-2 question for Tracy I have an LED (designed for 12V) wired up for the alarm light, and = it comes on (not flashing, steady) at what seems to be about half = brightness when power is applied to the EM-2. =20 Hi Bill, I had the exact same problem with the current EM-2 (all in one), but = not with the earlier one (separate electronics box). In both cases, I = used the exact same super bright LED's from the Shack of Rat. =20 In talking to Tracy, my understanding is that the alarm signal pin = is on a 5V pull up, with a 10k ohm resistor. When the EM-2 wants the = light on, it grounds the pin, but when it's "off", the pin would be = sitting at 5V. If you tie the light to 12V, then there's a 7V potential = across the light, with a 10k ohm resistor in series. This will allow = some current to flow, and would probably not be noticeable on an = incandescent lamp, but for LED's, it will appear to be on, but dim. =20 The fix was to use one of the EM-2 5V outputs for the LED alarm = light power. This gives no voltage differential when the light is = supposed to be off, and 5V differential when on. =20 If you are using a pre-packaged LED that's made for 12V, and you use = 5V instead, it will work but will be dimmer than it would have been with = 12V. You may have to use a different LED. =20 Tracy may also have a better answer now, so stand by for the real = answer :-) Cheers, Rusty (single rotor engine currently installed on the hanger floor) ------=_NextPart_000_0073_01C69E8C.99CE4500 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Rusty got it right (as usual).  I had incandescent lights in = mind when=20 the circuit was designed but LEDs will work as long as the limitations = pointed=20 out by Rusty are observed. 
 
Tracy
----- Original Message -----
From: Bill=20 Schertz
To: Rotary motors in = aircraft
Sent: Sunday, July 02, 2006 = 11:15=20 PM
Subject: [FlyRotary] Re: EM-2 = question=20 for Tracy

Thanks Rusty, that describes the = behavior=20 exactly. 12V supply, 12V prepackaged LED that glows dimly when power = is=20 applied to EM-2.
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
From:=20 Russell Duffy
To: Rotary motors in = aircraft=20
Sent: Sunday, July 02, 2006 = 9:01=20 PM
Subject: [FlyRotary] Re: EM-2 = question=20 for Tracy

I have an LED (designed for = 12V)=20  wired up for the alarm light, and it comes on (not flashing, = steady)=20 at what seems to be about half brightness when power is applied to = the=20 EM-2.  
 
Hi Bill,
 
I had the exact same problem with the = current EM-2=20 (all in one), but not with the earlier one (separate electronics = box). =20 In both cases, I used the exact same super bright LED's from the = Shack=20 of Rat. 
 
In talking to Tracy, my understanding is = that the=20 alarm signal pin is on a 5V pull up, with a 10k ohm resistor.  = When the=20 EM-2 wants the light on, it grounds the pin, but when it's "off", = the pin=20 would be sitting at 5V.  If you tie the light to 12V, then = there's a 7V=20 potential across the light, with a 10k ohm resistor in series.  = This=20 will allow some current to flow, and would probably not be = noticeable on an=20 incandescent lamp, but for LED's, it will appear to be on, but=20 dim.  
 
The fix was to use one of the EM-2 5V = outputs for=20 the LED alarm light power.  This gives no voltage=20 differential when the light is supposed to be off, and 5V = differential=20 when on.  
 
If you are using a pre-packaged LED = that's made for=20 12V, and you use 5V instead, it will work but will be = dimmer=20 than it would have been with 12V.   You may have to use a=20 different LED. 
 
Tracy may also have a better answer now, = so stand=20 by for the real answer :-)
 
Cheers,
Rusty (single rotor engine currently = installed on=20 the hanger=20 floor)
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