Re: Yet another 'replacing carbon resistors with metal film' question....

Richard Knoppow

This resistance to pulse current seems to be about the only virtue carbon comp resistors have. I don't know why. Most carbon film resistors will take tremendous overloads but as steady state. I worked in resistor manufacture many years ago. We made mil spec carbon film and established reliability metal film parts. Carbon film resistors would run at red heat without damage.

On 12/29/2020 9:35 AM, fiftythreebuick wrote:
Probably not a factor in this case, but in some cases we have found that metal film resistors (of the same value/wattage as the original carbon comp resistors) would blow open when exposed to high inrush current transients while carbon comp resistors would live in the same environment just fine. We first discovered this when working on the power supply of a 555. Multiple metal film resistors blew while a used carbon comp from a junker instrument stayed in there just fine.

Just for what it's worth....


Richard Knoppow

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