Re: [Phys-l] Detecting ultrasonic ring tones

[Bernard Cleyet <bernardcleyet@redshift.com>]

Diode rectification in a poor connection or from a diode in the  
amplifier.

This thread is peripheral to many of our threads on teaching  
philosophy and especially my peeve.  Parents that demand results via  
NCLB and then give them radio 'phones.  OTOH a 'phone is useful in  
the case of the rare armed invasion.


bc who spent some time tracking down the "diode" in an amplifier  
system that was "detecting" a local am station. (ca. 1950), and hears  
zilch above 3k Hz.

p.s.  Method 1. (collective punishment) reminds me school is a model  
of an unwelcome occupying force.  Unfortunately, the students can't  
apply a Geneva convention.


On 2008, Apr 22, , at 15:38, Marc "Zeke" Kossover wrote:
> Explaining why a gigahertz signal is
> detectable this way is more of a challenge.