[amsat-bb] Re: Yaesu 5400B Az-EL rotor controller Lamps

Howard Kowall hkowall at shaw.ca
Fri Nov 13 08:49:59 PST 2009

The resistor value, R is given by:

      R = (VS - VL) / I

VS = supply voltage
VL = LED voltage (usually 2V, but 4V for blue and white LEDs)
I = LED current (e.g. 20mA), this must be less than the maximum permitted

Here is the standard calculation



----- Original Message ----- 
From: "Vince Fiscus, KB7ADL" <vlfiscus at mcn.net>
To: <amsat-bb at amsat.org>
Sent: Friday, November 13, 2009 10:29 AM
Subject: [amsat-bb] Yaesu 5400B Az-EL rotor controller Lamps

> Someone a while back mentioned using LED's as replacements for the meter
> lamps when they burn out. Can't remember who it was.  Anyway, if you're
> still on the list, what value of resister did you use in series with the
> LED's?  I think the OEM lamps were around 14 or 15 volts.
> Thanks
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