Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: HV Ceramic capacitors  (Read 1695 times)
K3HVG
Member

Posts: 149




Ignore
« on: February 02, 2005, 04:51:27 AM »

Although I've been around the barn more than once, I've may well have missed some salient points in selecting the correct type of capacitor for HV DC blocking and bypassing.  Specifically, the type (not value or voltage rating) recommended/required for A. DC Blocking a Pi tank, and B. bypassing the RF choke.  I think item A. is the real question, however.  Thanks for your insights.
Logged
K0BG
Member

Posts: 10248


WWW

Ignore
« Reply #1 on: February 02, 2005, 06:10:59 AM »

I have built 5 amplifiers and in each case I used ceramic dipped capacitors rated at either 5KV or 10KV depending on the plate voltage. Some commercial amps use door-knob types which is fine too.

Alan, KØBG
www.k0bg.com
Logged

WA9SVD
Member

Posts: 2198




Ignore
« Reply #2 on: February 02, 2005, 09:05:12 AM »

Certainly, it will depend upon the power level, as well as voltage.  Commercial amps often use the "door-knob" type capacitors because they are (usually) designed to handle higher RF currents (such as in a KW+ amp) and would be a good choice for the DC Blocking capacitor; the choke bypass (SHOULD) have to handle much less RF so it doesn't have to be quite so heavy-duty, and a suitably rated ceramic capacitor (as suggested) should work fine.
Logged
WB2WIK
Member

Posts: 21837




Ignore
« Reply #3 on: February 02, 2005, 09:48:14 AM »

Rather than reinvent the wheel, I usually use the same type capacitors for these applications as the better manufacturers do, since they spent design time doing DVT to verify what works.

RF Parts sells suitable HV caps called out for these apps, and Ameritron sells every part used in their amplifiers as "spare parts" for reasonable prices, so I've bought stuff from them, too.  I remember Tom, W8JI, who designed some of the Ameritron amps, recommended a particular component and I found it was used in the AL-82, AL-1200 and AL-1500 amps, so I just ordered that part from Ameritron.  It was only a few bucks.

WB2WIK/6
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!