What's Inside Aircraft Jumper Cables?

[Paul Dow (Remove Caps in mail address)]

A friend of mine has some very nice aircraft auxiliary power cables, and
he was going to take it apart and remove the insulation for the scrap
copper. After seeing how nice it is (4/0 stranded cable), he put it back
together, but he noticed something strange. Inside the plug connector
was a 50 ohm resister in series with a diode connected across the two
cables. Copper pins were inserted into the braided wire to make the
connection.

Does anyone know what that is for?

Thanks

[Eduardo K.]

In article >,
Paul Dow (Remove Caps in mail address) > wrote:
>A friend of mine has some very nice aircraft auxiliary power cables, and
>he was going to take it apart and remove the insulation for the scrap
>copper. After seeing how nice it is (4/0 stranded cable), he put it back
>together, but he noticed something strange. Inside the plug connector
>was a 50 ohm resister in series with a diode connected across the two
>cables. Copper pins were inserted into the braided wire to make the
>connection.
>
>Does anyone know what that is for?
>

Reverse polarity protecion? Connect it wrong and diode shorts and fuse
upstream blows?



--
Eduardo K. | Darwin pone las reglas.
http://www.carfun.cl | Murphy, la oportunidad.
http://ev.nn.cl |
| Yo.

[GeorgeB]

On Thu, 18 Oct 2007 15:17:33 +0000 (UTC), Eduardo K.
> wrote:

>In article >,
>Paul Dow (Remove Caps in mail address) > wrote:
>>A friend of mine has some very nice aircraft auxiliary power cables, and
>>he was going to take it apart and remove the insulation for the scrap
>>copper. After seeing how nice it is (4/0 stranded cable), he put it back
>>together, but he noticed something strange. Inside the plug connector
>>was a 50 ohm resister in series with a diode connected across the two
>>cables. Copper pins were inserted into the braided wire to make the
>>connection.
>>
>>Does anyone know what that is for?
>>
>
>Reverse polarity protecion? Connect it wrong and diode shorts and fuse
>upstream blows?

I'd guess either a zener or transzorb with 50 ohms to limit current?
50 ohms, 25 volts, 0.5 amp ...

[Larry Dighera]

On Thu, 18 Oct 2007 09:24:42 -0400, "Paul Dow (Remove Caps in mail
address)" > wrote in
>:

>A friend of mine has some very nice aircraft auxiliary power cables, and
>he was going to take it apart and remove the insulation for the scrap
>copper. After seeing how nice it is (4/0 stranded cable), he put it back
>together, but he noticed something strange. Inside the plug connector
>was a 50 ohm resister in series with a diode connected across the two
>cables. Copper pins were inserted into the braided wire to make the
>connection.
>
>Does anyone know what that is for?
>
>Thanks

It sounds like a surge suppressor or snubber circuit to me.

[Paul Dow (Remove Caps in mail address)]

That seems to make sense. I wasn't familiar with snubber circuits, nor
even the word snubber, until I looked it up now. You wouldn't want the
voltage spike hitting the aircraft when plugging in the outside power,
so that probably limits the rate of voltage change.

I don't think it protects against reverse polarity since it doesn't look
like something that gets replaced easily if it breaks. The parts are
quite small for current limiting too.

Thanks everyone.
I'll put it back in.

Larry Dighera wrote:
>
> It sounds like a surge suppressor or snubber circuit to me.
>