On 2/8/2020 4:15 AM, Rob Atkinson wrote:
Why do hams mindlessly use ferrite on everything, including lines that
only have DC on them? What happened to RF chokes and bypass
capacitors, which when the correct component values and specifications
are used (value, current handling and voltage rating), will work
better and cost much less?
You may be confusing differential mode with common mode. And with modern
electronics, DC often has a strong AC component. That's what's going on
with variable speed motor controllers and switch mode power supplies.
And, sadly, lots of equipment is poorly designed, with common mode
emissions and common mode susceptibility. Ferrite chokes solve common
mode problems. Traditional RF chokes and bypass caps solve differential
mode problems.
73, Jim K9YC
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