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

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Non-Polarized Tantalum question  (Read 2815 times)
W6AOA
Member

Posts: 35




Ignore
« on: November 17, 2013, 04:03:20 PM »

I am modifying a preamplified mic to work with an Icom-730 and will be using the internal 8v (supplied by the 730 on pin 2 of the mic connector).  I need to place a 1uf Non-polarized Tantalum cap at the hot mic element.  The question is can I use a polorized electrolytic capacitor at that point and if so, what polarity (+ or - toward the mic element).  I'm confused about the importance of it being NP Tantalum and if it really maters...   HELP..
TNX
Ed W6AOA
Logged
KB4QAA
Member

Posts: 2269




Ignore
« Reply #1 on: November 17, 2013, 06:26:49 PM »

Hmm.  I've never heard of a tantalum cap being required for microphone application.

If the application specifies a non-polarized Tantalum, then I don't think you would want to use a polarized electrolytic. 

Look for non-polarized alternatives, like mylar film, or metallized film caps.  The main reason electrolytics are used is simply the higher range of capacitance they offer.   If you can find a non-polarized cap with the same value, then use it. 

bill
Logged
K2OWK
Member

Posts: 1039




Ignore
« Reply #2 on: November 17, 2013, 09:32:52 PM »

Two .5 uf polarized electrolytic capacitors put in parallel to back to back (+ to -/ - to +) will work as a non polarized 1 uf capacitor. This set up is used for filter networks on speakers. It should work on a mike as well as long as the maximum voltage is observed. Cheep way to do it.

Hope this helps.

K2OWK
Logged
G3RZP
Member

Posts: 4391




Ignore
« Reply #3 on: November 18, 2013, 04:08:17 AM »

K2OWK,

You mean two polarised 2 microfarad tantalums back to back in SERIES. In parallel, they both get reverse voltage!
Logged
TANAKASAN
Member

Posts: 933




Ignore
« Reply #4 on: November 18, 2013, 06:43:11 AM »

I'm guessing that your microphone element has two connections, ground and a combined output and supply pin. If this is the case then use a standard 1uF polarized capacitor with the positive end connected to the microphone element. Don't forget the series resistor in the supply line, 2.2K ohm should be about right.

https://upload.wikimedia.org/wikipedia/commons/5/57/Electret_condenser_microphone_schematic.png

If your microphone element has three connections (rare but possible) then it probably doesn't matter which way round you connect the cap as the signal on the output pin will be at a very low level.

Tanakasan
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!