Homepage - RF Cafe
Webmaster: Kirt Blattenberger | KB3UON | Sitemap | ©1996-2014
Menu below is just a small sample of what is here!
 
Custom Search
More than 10,000 searchable pages indexed.
•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

ampifier test setup procedure - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

Below are all of the forum threads, including all the responses to the original posts.


 Post subject: ampifier test setup procedure
Posted: Mon Oct 22, 2007 7:41 am 
 
Lieutenant
User avatar

Joined: Thu Oct 11, 2007 7:58 pm
Posts: 4
Hi,

When testing an amplifier I was told to connect dc, turn dc on and then connect testing cables. Is this the right procedure?

Thanks.


 
   
 
 Post subject:
Posted: Tue Oct 23, 2007 3:22 pm 
 
Captain
User avatar

Joined: Sun Mar 19, 2006 5:25 pm
Posts: 23
Location: Burnaby
I don't think this procedure fits for all the amplifiers such a high power one. You may check the specification of your instrument to ensure it.


 
   
 
 Post subject:
Posted: Wed Oct 24, 2007 7:33 am 
 
General
User avatar

Joined: Fri Feb 17, 2006 12:07 pm
Posts: 268
Location: London UK
Feng is right: many medium to high power amps have a stability margin that is both source and load sensitive: that is they become unstable at certain load and source combinations of Reflection Coefficient magnitude and phase. I think a dude called Linvill first did the analysis of this for soldstate amps.
If the test cables are long and/or have extremely good dielectric insulation, it is possible that static charge can build up between the centre and outer. It therefore good practice to short the test cable between inner and outer before connecting the cables to the amp. Having connected them without risk of static damage, I would next turn the DC power on having ensured the source and load have a reasonably good match.


 
   
 
 Post subject:
Posted: Sun Jan 27, 2008 3:36 am 
 
Site Admin
User avatar

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 406
Location: Germany
Hello Asaf,

Since I also come from Israel and have worked in several RF companies,
I know the root of the fairy tale instruction you were told:

It is the fear that there might be an input power applied to the amplifier before power supply is applied, namely when the amplifier is connected as part of a cascade. When several amplifiers are connected in cascade that is the right thing to do but NOT when testing an amplifier as a stand alone unit.

What the other posts mentioned is 100% correct.





Posted  11/12/2012
A Disruptive Web Presence

Custom Search
Over 10,000 pages indexed! (none duped or pirated)

Read About RF Cafe
Webmaster: Kirt Blattenberger
    KB3UON

RF Cafe Software

RF Cascade Workbook
RF Cascade Workbook is a very extensive system cascaded component Excel workbook that includes the standard Gain, NF, IP2, IP3, Psat calculations, input & output VSWR, noise BW, min/max tolerance, DC power cauculations, graphing of all RF parameters, and has a graphical block diagram tool. An extensive User's Guide is also included. - Only $35.
RF system analysis including
frequency conversion & filters

RF & EE Symbols Word
RF Stencils for Visio

Product & Service Directory
Personally Selected Manufacturers
RF Cafe T-Shirts & Mugs

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel
Your RF Cafe Progenitor & Webmaster
Click here to read about RF CafeKirt Blattenberger... single-handedly redefining what an
                                 engineering website should be.

View the YouTube RF Cafe Intro Video Carpe Diem! (Seize the Day!)

5CCG (5th MOB): My USAF radar shop

Airplanes and Rockets: My personal hobby website

Equine Kingdom: My daughter Sally's horse riding website