[ARC5] More on receiver current drain.

[jmfranke]

250V times .013A = 3.25W

120V times .013A = 1.56W

130V times .013A = 1.69W

1.56W + 1.69W = 3.25W

Without a heat sink, the Zener diodes would get hot.

John  WA4WDL

--------------------------------------------------
From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
Sent: Saturday, January 08, 2011 9:44 PM
To: <Arc5 at mailman.qth.net>
Subject: [ARC5] More on receiver current drain.

> Well, Mouser got my Zeners to me today.
>
> Paired up one 120 V and one 130 V and hung them across the output. Total
> current drain at 250 VDC output was 13 mA and voltage dropped was 69
> volts.
>
> The output voltage started slowly climbing past 250 VDC, and kept going,
> while the Zeners got too hot to touch within a few minutes.
>
> Total power dissipated in 10 watts worth of Zeners was less than 1 watt
> (0.897).
>
> The only thing I suspect is that one of the two diodes in the rectifier is 
> bad...
>
> :-(
>
> Ken W7EKB
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