I may have... unintentionally... made a transformer.

[corrado33]

I work with high temperature fuel cells and recently I've been fabricating an oven to bring a newly built apparatus up to 750-800 C. I'm actually using two ovens, an outer oven and an inner oven. The outer oven heats the entire assembly up to 20-30*C below the required temp, and the inner oven brings it up to temp. The temperature of the cell is very slow to respond to changes in current for the outer oven, hence the use of the inner oven.

Anyway, I've had a problem with inner ovens breaking recently (I'm in the development stage, it happens) and the other day, while the device was at 650C or so, the inner oven failed. (Actually, now that I think about it it may not have failed...). Anyway, I went to measure the resistance and I was getting -300 kOhms. Yes, you read that correctly, negative resistance.

I didn't think anything of it until I read the "Stupid things you've heard people say" thread. I guess I created a transformer. Next time I heat it up I'll have to measure the voltage.

Anyway, thought it was funny.

[T3sl4co1l]

If you measured it while it was still hot, the meter might've been confused by thermal or chemically generated voltage.  Just a few microamps would do.

Tim

[retrolefty]

If you measured it while it was still hot, the meter might've been confused by thermal or chemically generated voltage.  Just a few microamps would do.

Tim

 Ah, acting like a giant thermocouple?

Next time you measure resistance while hot try both polarity to see if it is a active voltage effecting the resistance reading. Then measure DC voltage to see if there is a small Seebeck effected voltage presence at high temp.