Jensen Aluminium Paper Oil Capacitors Positive Temperature Coefficient

[sharpi31]

I left four new Jensen 20uF 100V aluminium foil paper in oil caps in my car overnight and the temperature dropped below freezing. Out of interest I thought I'd measure the capacitance cold and then a few hours later at room temperature.

Cap Cold (0degrees C) Warm (15degrees C)
1 19.3uF 19.5uF
2 19.4uF 19.6uF
3 19.3uF 19.4uF
4 19.5uF 19.6uF

Hardly a revolutionary result but I thought I'd post on the basis that someone may find this interesting. I wonder how much values drift at the higher temperatures inside tube amps etc.

Looking forward to trying them for line level coupling.

 

[DF96]

My guess is that ESR will change with temperature more than capacitance. The capacitance of an electrolytic is set mainly by the thickness and composition of the oxide layer, which won't change much with temperature. The ESR comes from things like the electrolyte chemistry.

 

[davidsrsb]

No oxide layer here. These are two sheets of foil with paper and oil separator, wound into a cylinder. The oil Er will be temperature sensitive.

 

[DF96]

Sorry, my mistake. Not an electrolytic.