[ARC5] Building a power supply for an ARC setup

[Brian Clarke]

The Zener is there to avert safety problems if a choke in the negative line 
of a power supply goes OC. It is not a clipping device. Different deal.
If you are concerned about ac ripple taking the Voltage drop too high, put a 
12 V 6 W lamp in series with the Zener diode.
73 de Brian, VK2GCE.

On Wednesday, April 24, 2013 1:04 AM, you said:


> Isn't there a NE-2 across the output transformer primary on some (all)
> ARC-5 receivers to limit the P-P voltage excursions?
>
> If so, same deal.
>
> -John
>
> ===================
>
>
>
>> I have never seen the suggestion of putting a zener diode across the 
>> choke
>> before.
>> An interesting idea, but the average DC voltage drop across the choke is
>> less than the
>> actual voltage swing across it. Particularly if you have a choke input
>> filter.
>>
>> 73
>> Bill wa4lav
>>
>> ________________________________________
>> From: arc5-bounces at mailman.qth.net [arc5-bounces at mailman.qth.net] on
>> behalf of Brian Clarke [brianclarke01 at optusnet.com.au]
>> Sent: Tuesday, April 23, 2013 7:09 AM
>> To: David Stinson; arc5 at mailman.qth.net
>> Subject: Re: [ARC5] Building a power supply for an ARC setup
>>
>> Good warning, Dave.
>>
>> So, calculate the maximum Voltage drop across the choke and put a Zener
>> diode across it that has a breakdown Voltage a bit above that - just in
>> case - even put a small incandescent lamp in series with the Zener to
>> indicate when the choke has gone OC. A 39 V Zener carrying 400 mA will
>> need
>> to be rated at 20 W. Much cheaper than buying a modern-day 10 H choke.
>>
>> On another matter, the Eagle landed today. Well packed. Many thanks.
>> Another
>> project can race to fruition!
>>
>> 73 de Brian, VK2GCE.
>>
>> On Monday, April 22, 2013 11:52 PM, you said:
>>
>>
>>>
>>> ----- Original Message -----
>>>
>>>> I would suggest a 10 H choke if you can. And if you are worried about
>>>> its
>>>> insulation after years of solitary shelf life, put it in the negative
>>>> lead.
>>>
>>> Respectfully:
>>> The following sounds obvious but with this old gear, it's not.
>>> Every year that goes by, I'm finding more Hi-Z grounds.
>>> Make sure you have a reliable Lo-Z ground connection
>>> between any external supply and the rig.
>>> If the old choke (or any B- lead) opens or goes Hi-Z
>>> and the bond between the supply and the rig is not a good one,
>>> the whole rig will be at B+ to supply ground.
>>> Please don't ask me how I know about this ;-)
>>
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