Return-Path: Received: from out006.verizon.net ([206.46.170.106] verified) by logan.com (CommuniGate Pro SMTP 4.2) with ESMTP id 384132 for flyrotary@lancaironline.net; Sun, 29 Aug 2004 23:40:10 -0400 Received-SPF: pass receiver=logan.com; client-ip=206.46.170.106; envelope-from=finn.lassen@verizon.net Received: from verizon.net ([4.12.145.173]) by out006.verizon.net (InterMail vM.5.01.06.06 201-253-122-130-106-20030910) with ESMTP id <20040830033939.ZFIS22385.out006.verizon.net@verizon.net> for ; Sun, 29 Aug 2004 22:39:39 -0500 Message-ID: <4132A174.50402@verizon.net> Date: Sun, 29 Aug 2004 23:39:32 -0400 From: Finn Lassen User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624 Netscape/7.1 (ax; PROMO) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: alternator connections References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------050802090002060307050502" X-Authentication-Info: Submitted using SMTP AUTH at out006.verizon.net from [4.12.145.173] at Sun, 29 Aug 2004 22:39:39 -0500 This is a multi-part message in MIME format. --------------050802090002060307050502 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Don't remember, but 470 ohms 1/2 or 1/3 watts plain carbon should do. Depends on max allowable current for the LED and its rated voltage. Lets assume max 16 volts. LED voltage 2.3 volts and 0.030 amps (30 mA): (16 - 2.3) / 0.03 = 457 ohms. 470 ohms is a standard value (390 ohms is next lower value, which might be better). Assuming max battery voltage of 13 volts and LED voltage of 2.3 volts: (13 - 2.3) / 0.030 = 357 ohms. P = I * I * R = 0.030 * 0.030 * 470 = 0.42 watts. P = I * I * R = 0.030 * 0.030 * 390 = 0.35 watts. The above examples should give you enough info to recalculate once you have the LED specs. The resistor is used to limit the current through the LED. The higher the resistor value (ohms) the less current. Finn paul wrote: > Thank you very much for the info, Finn....sounds even simpler than a > diode and a relay. Do you have any information regarding the resistor? > (type, resistance, bought at Radio Shack, etc)? Thanks again. Paul > Conner > > ----- Original Message ----- > From: Finn Lassen > To: Rotary motors in aircraft > Sent: Sunday, August 29, 2004 2:01 PM > Subject: [FlyRotary] Re: alternator connections > > Has not been true for me. LED and resistor in series only has been > working well from day 1. > I beleive my Mitsubishi is the stock RX-7 alternator. > > Finn > --------------050802090002060307050502 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Don't remember, but 470 ohms 1/2 or 1/3 watts plain carbon should do.

Depends on max allowable current for the LED and its rated voltage.

Lets assume max 16 volts.
LED voltage 2.3 volts and 0.030 amps (30 mA):
(16 - 2.3) / 0.03 =  457 ohms.

470 ohms is a standard value (390 ohms is next lower value, which might be better).
Assuming max battery voltage of 13 volts and LED voltage of 2.3 volts:
(13 - 2.3) / 0.030 =  357 ohms.

P = I * I * R =  0.030 * 0.030 * 470 =  0.42 watts.
P = I * I * R =  0.030 * 0.030 * 390 =  0.35 watts.

The above examples should give you enough info to recalculate once you have the LED specs.
The resistor is used to limit the current through the LED. The higher the resistor value (ohms) the less current.

Finn

paul wrote:
Thank you very much for the info, Finn....sounds even simpler than a diode and a relay. Do you have any information regarding the resistor? (type, resistance, bought at Radio Shack, etc)?   Thanks again.  Paul Conner
----- Original Message -----
Sent: Sunday, August 29, 2004 2:01 PM
Subject: [FlyRotary] Re: alternator connections

Has not been true for me. LED and resistor in series only has been working well from day 1.
I beleive my Mitsubishi is the stock RX-7 alternator.

Finn
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