You dont need 5W.
Just BUY a pair of Ohmite 47 Ohm 2W OY series from Mouser as others do.
They have no minimum and if you call in the order ask for USPS First Class
Mail so you dont get hit with a $8+ UPS minimum.
----- Original Message -----
From: "Joe" <nss@mwt.net>
To: "Bryan Swadener" <bswadener@yahoo.com>; <amps@contesting.com>
Sent: Saturday, August 11, 2018 12:46 PM
Subject: Re: [Amps] 47 Ohm 5 watt
Yeah temp would be an issue, these will be replacing these in a SB-220
amp.
Joe
Sig
The Original Rolling Ball Clock
Idle Tyme
Idle-Tyme.com
http://www.idle-tyme.com
On 8/9/2018 12:54 PM, Bryan Swadener via Amps wrote:
Be careful of the temperature derating. The datasheet says they start to
derate at 25°C and derate to zero at 155°C. Caddock and others produce
similar power resistors. Kanthal/Globar produces suitable single units
but, I've not heard of a source for small quantities. However, a coupla
100Ω/2W carbon composition resistors can be used in parallel. Ebay seller
'bigsmythe74' has new old stock Allen-Bradley but, he wants $4/each.
Sorting by price, I see he has 91Ω/2W available for $1.25 each
(http://www.ebay.com/itm/400003772794). Add $3.50/order shipping to USA.
vy 73, Bryan WA7PRC
----------------------------------------------------------------------
Date: Wed, 08 Aug 2018 16:50:37 +0000
From: Manfred Mornhinweg <manfred@ludens.cl>
To: amps@contesting.com
Subject: Re: [Amps] 47 Ohm 5 watt
Joe,
I hope someone has in their parts box. (2) 5 Watt 47 ohm non inductive
resistors.
Actually I do have a few, apparently metal oxide, but shipping them to
you would cost more and take much longer than if you buy them...
Maybe you can use this one:
https://www.digikey.com/product-detail/en/ohmite/TNP10SC47R0FE/TNP10SC47R0FE-ND/6165413
It's 10W, but still small enough and not too expensive. You can either
bolt it to the chassis, or on a little aluminium sheet that acts as
heatsink, shaped and bent to fit the space you have. These resistors
have lower inductance than old-style "non-inductive" ones, due to their
smaller size. Of course you destroy that advantage if you have to use
long wires to connect them...
Or you can assemble them from several 2W film resistors of properly
chosen values, combined in parallel. Those are very common and
inexpensive. Or use a bunch of even smaller resistors.
Manfred
========================
Visit my hobby homepage!
http://ludens.cl
========================
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
---
This email has been checked for viruses by AVG.
https://www.avg.com
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|