On 2/17/2025 9:12 PM, Jim Brown wrote:
Watch out for regulated PSUs, which tend to be noisy.
... Only those that use a switcher for the regulator. I've encountered
some noisy LM723 regulator chips, though; I had to use a different
manufacturer's chips to get rid of the HF oscillations they often
showed. Linear regulator ICs (three-terminal -types) also can generate
HF noise but it's easily suppressed with (usually) very small/low
voltage 0.01 uF disc or leaded ceramic caps from input and output to the
ground pin, with very short leads, right on the IC. Once inna while, a
tiny ferrite bead right on the wire soldered to the chip might be
needed, but rarely, in my experience. An oscilloscope is often a big
help to find and suppress a noisy regulator chip.
Steve, K0XP
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
|