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-   -   Resistor Wattage? (https://www.vintage-radio.net/forum/showthread.php?t=182430)

Murphy Maniac 31st Jul 2021 10:05 pm

Resistor Wattage?
 
1 Attachment(s)
Good Evening All,
Can someone please help by telling me the wattage of the 820R resistor in the photo?
Will it be comfortable at 4W?
Thanks.

GrimJosef 31st Jul 2021 10:27 pm

Re: Resistor Wattage?
 
It's a vintage carbon film resistor (used to be called 'cracked carbon' and/or labelled 'high stability'), made by Piher. I'm afraid it won't be comfortable at 4W. They certainly made them in 1/2W, 1W and 2W versions and possibly in smaller sizes too. But I don't think any were rated higher than that. I think yours is the 2W size, but I'd need to extract one from storage and measure it to be sure.

Cheers,

GJ

Cobaltblue 31st Jul 2021 10:32 pm

Re: Resistor Wattage?
 
I agree with GJ looks like a 2 Watt'r

I think I would be using a nice 7W wire wound if it were to be dissipating 4W continuously.

Cheers

Mike T

60 oldjohn 31st Jul 2021 10:44 pm

Re: Resistor Wattage?
 
Quote:

Originally Posted by GrimJosef (Post 1394462)
It's a vintage carbon film resistor (used to be called 'cracked carbon' and/or labelled 'high stability'), made by Piher. I'm afraid it won't be comfortable at 4W. They certainly made them in 1/2W, 1W and 2W versions and possibly in smaller sizes too. But I don't think any were rated higher than that. I think yours is the 2W size, but I'd need to extract one from storage and measure it to be sure.

Cheers,

GJ

I think GJ is correct, I have a packet branded "RS" 2W high stability carbon film, which I have just measured.

Crossed with Mike.

John

Murphy Maniac 1st Aug 2021 1:31 am

Re: Resistor Wattage?
 
Thanks for that, I very much feared that might be the case.
Having searched through the thousands of resistors which I have in stock, unfortunately, I have nothing suitable. 820 ohms, although a prefered value, does not seem to be available as 7W or 10W W/W.

HamishBoxer 1st Aug 2021 8:40 am

Re: Resistor Wattage?
 
That is a Radiospares 2W and No more.

radioman 1st Aug 2021 9:01 am

Re: Resistor Wattage?
 
RS have a few... e.g. https://uk.rs-online.com/web/p/throu...istors/4852962

Andy

Murphy Maniac 1st Aug 2021 11:54 am

Re: Resistor Wattage?
 
Brilliant, thanks Andy.


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