|
Title: temp coefficient factor for capacitors Post by: W9BHI on March 31, 2014, 10:05:35 AM I'm looking at some doorknob capacitors to use as a plate blocking cap in a tank circuit.
My choices are N750 or N3300. Wich are more suited for this application? Don W9BHI Title: Re: temp coefficient factor for capacitors Post by: KA2DZT on March 31, 2014, 10:11:05 AM Probably neither. Why are you trying to use a negative temp coeff. cap??
Fred Title: Re: temp coefficient factor for capacitors Post by: W9BHI on March 31, 2014, 10:24:33 AM That's all that is available in 500pf 7.5KV OR 15KV.
Don W9BHI Title: Re: temp coefficient factor for capacitors Post by: KA2DZT on March 31, 2014, 10:29:58 AM Good reason, I guess I would use the N750 at the highest voltage rating. Lets see what others may think about this. I'm sure we'll get more input on the subject.
Fred Title: Re: temp coefficient factor for capacitors Post by: W9BHI on March 31, 2014, 11:57:47 AM I figure that if it was a padder and changed value with temperature, that might be an issue.
Just being used as a bypass at the bottom of the plate choke or as a plate blocking cap in a PI output, a slight drift in value may not affect the tuning. Maybe? Don W9BHI Title: Re: temp coefficient factor for capacitors Post by: N2DTS on March 31, 2014, 02:00:14 PM I would not think it would matter under most uses. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Caps are not stable with temp unless they are npo, so regular caps change, just in the other (positive) direction. In really high Q tuned circuits, whatever was used would be best, since it was designed for that, but I cant think of anything that fits that description at HF except vfo's or maybe some sort of high Q filter. |