« U.K. Calls Kid Repellent a "Last Resort" | Main | Shake-to-Charge Torch Doubles as a Metal Detector »
David Merrill discovers unintended sound effects from an LED display:
"I didn't realize that an LED could make *audible* sound until my friend/colleague Sajid called me over to have a look. What can I say - it's true.. This is a circuit with NO SPEAKERS, making audible sound.
TrackBack URL for this entry:
http://www.electronicsweekly.com/cgi-bin/mt/mt-tb.cgi/23254
This page contains a single entry from the blog posted on March 11, 2008 12:17 PM.
The previous post in this blog was U.K. Calls Kid Repellent a "Last Resort".
The next post in this blog is Shake-to-Charge Torch Doubles as a Metal Detector.
Many more can be found on the main index page or by looking through the archives.
Subscribe to this blog's feed
Follow ElectronicsNews
Comments (4)
.. as opposed to *inaudible* sound?
Posted by Andrew | March 12, 2008 2:14 PM
I wonder if the noise is coming from ceramic capacitors (piezo electric effect) or from any coils in the circuit?
Posted by Steve Winder | March 12, 2008 5:09 PM
That would have been my guess, I have often seen this with very cheap switchmode psu designs, when the current is modulated.
Posted by Doug Allender | March 13, 2008 9:51 AM
>
Er, yes! Do you find ultrasound iritating?
Posted by Chris Halford | March 11, 2009 3:23 PM