cmassa
Posts: 162
Joined: 1/8/2002
From: Chico,
CA, USA
Status: offline
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Huh???
[QUOTE]Originally posted by szastoupil
This toroid is used for extra measure. You can purchase one from [URL=http://www.amidon-inductive.com/associates_prod_toroidal.htm]Amidon Associates[/URL] . The "140" is the outer diameter of the toroid, which is a requirement base on your wire size and the number of turns needed. And the "43" is the mix of the powdered iron core, which correlates to the the frequency cutoff of the core itself. Basically it is a low pass filter. I am not sure what the frequency range of the 43 is off hand. If you have access to an ARRL Handbook, the appendix has the broad frequency ranges for each color of core. Keep your eyes peeled at the next hamfest that you attend a Yellow or Red core. The core added in the QST article is to attenuate the high frequency radiated emissions from the switching power supply so they don't end up as "birdies" in the ham radio. For the charger application, it probably isn't necessary, but I am not advocating unintentional radiators either. In this case you aren't worried about "birdies" in your battery charger. In the professional design world, we would worry about the emission levels affecting the receiver and affecting the battery charger micro controller. I hope this is enough info.
Scott
ARS KB0KFX [/QUOTE]
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Chris Massa
Butte R/C Club
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All Forums >> Radios, Batteries, Clubhouse and more >> Batteries & Chargers >> Great Planes new DC charger/cycler 
Great Planes new DC charger/cycler - 
Please help! - 
