Inductors are the most common noise source, but ceramic capacitors, especially ones with high dielectric constant dielectrics (not NP0/C0G types), can also make noise if the voltage across them is changing significantly. On Wed, Nov 9, 2011 at 12:40 PM, Herbert Graf wrote: > On Wed, 2011-11-09 at 19:30 +0200, Yigit Turgut wrote: >> Hi all, >> >> I have a product and everything works as expected except one thing ; >> there is a hiss/noise coming from the circuit (not the speakers, >> actual circuit). I recorded and analyzed the sound, it is an >> approximately 2khz signal (clock is 48mhz) but not sure which >> component it is originating from. My first guess was it could be a >> capacitor because there aren't many analog components on the board but >> it could be another one as well. >> >> Has anyone encountered such a behavior ? > > Certainly. Many power supplies have an audible sound. Most common things > that generate sound are windings. Inductors, transformers and chokes are > the biggest ones. Do you have any of those on your board? > > Thanks, TTYL > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .