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I have this wire-wound power resistor that appears to be either ceramic or porcelain in construction with a soft brown plastic or vinyl like coating. I want to find out its power rating. My meter shows about 5.2 ohms. A Google search for 160DR5WL returns nothing.

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    \$\begingroup\$ How much current do you want to put through the thing? I'll bet you get nowhere close to the limit with anything you can produce. \$\endgroup\$ – AngryEE Mar 23 '11 at 14:10
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    \$\begingroup\$ I was considering the possibility of using this as a dummy speaker load so I could silently troubleshoot guitar amplifiers in my apartment if I needed to. Guitar amps typical range from 50 to 120 watts. \$\endgroup\$ – Prof. Meow Meow Mar 23 '11 at 14:57
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I cannot say for sure who the manufacturer of this part is. I've used many of these sorts of resistors in my career, so my speculation below is made with a fair degree of confidence.

Renfrew wire-wound resistors that are 8" long and 1 1/8" in diameter are rated at 160W, which correlates with the 160D marking on the part. I'd hazard to guess that it's rated 160W (or very close to that).

R5 on these sorts of parts usually implies 0.5 ohms. The other marks are probably tolerance and packaging codes. If you measure higher, and your meter is OK, the resistor may be somwhat fried.

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  • \$\begingroup\$ Most meters aren't real good at measuring below 1 ohm anyways... \$\endgroup\$ – Kevin Vermeer Mar 23 '11 at 14:05
  • \$\begingroup\$ I've used a bank of Rohm resistors in the same package that were rated at 120W, so we're in the ballpark with 160. \$\endgroup\$ – Kevin Vermeer Mar 23 '11 at 14:06
  • \$\begingroup\$ Thanks! That seems like a fairly good evidenced based ballpark figure to me. Although not shown in the photo, someone did write 4.8 ohms with a marker on the side of it. I'll have to double check the specifications for my meter when I return home tonight. \$\endgroup\$ – Prof. Meow Meow Mar 23 '11 at 14:51
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    \$\begingroup\$ @reemrevnivek If he first measures the short circuit resistance of the multimeter leads and internal circuity and subtracts it from the result then I would expect him to get a good estimate after. \$\endgroup\$ – jpc Mar 23 '11 at 15:05
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    \$\begingroup\$ You can also take power supply with current limiting, put 1 Amp through it and measure the voltage. That should be very accurate. \$\endgroup\$ – jpc Mar 23 '11 at 15:07
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Connect it to a suitable power supply and check it for yourself. You will need to judge when the temperature is excessive for your application. You could check against resistors of a similar size and value from the usual suppliers like Digi-Key.

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