[HomeBrew] Neon bulb code practice oscillators

[Brian Carling]

Here's one more link - although THIS is for a dual tone 
oscillator and it will be more useful as an alarm than for 
use as a code practice oscillator.

http://www.af4k.com/imag/qbird.gif
http://www.af4k.com/imag/qbird3.gif
http://www.af4k.com/imag/qbirdsch.jpg
http://www.af4k.com/imag/qbrdsch2.jpg

The sound that it makes can be heard here:
http://www.af4k.com/sounds/QBIRD2.mp3
http://www.af4k.com/sounds/qbird2.wav

Note that the Heath HW-16 used an oscillator like these for the sidetone!

On 17 May 2004 at 13:03, James E. Kearman wrote:

> > Can anyone point me towards a website with a schematic for a code
> > practice oscillator using a neon bulb, charged and discharged
> > through capacitors, resistors and a key?
> 
> Hi, Bill,
> 
> This is called a relaxation oscillator. The capacitor is charged
> through a resistor until its voltage equals the voltage at which the
> neon bulb turns on. When the bulb turns on, it discharges the
> capacitor, causing the bulb to go out, and the process starts again.
> Here are a couple of links.
> 
> 73,
> 
> Jim, KR1S
> 
> http://www.oberlin.edu/physics/catalog/demonstrations/em/neonosc.html
> 
> http://en.wikipedia.org/wiki/Neon_light
> 
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