[RFI] Any LM338 Regulator RFI?

Tim Groat tcgroat at mesanetworks.net
Tue Jan 10 21:05:30 EST 2006


The LM338 is a linear regulator so it won't be a noise generator if it's 
stable. Use proper RF bypassing to prevent oscillation, taking care to keep 
the bypass cap leads leads short.

The same bypass caps will also help keep transmitter RF out of the 
regulator. I've had a power supply go out of regulation when transmitting 
because of RF pickup even at QRP power levels. Adding bypass caps on the 
power supply's input and output leads cured the problem.

73,
--Tim (KR0U)

>kd4e <kd4e at verizon.net>:
>
>Should I be concerned about any RFI if I were to use a LM338 in a dc-dc 
>power supply?





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