cuckoo sound generator

[phil7]

I found the schematic for the cuckoo sound generator at the electronics-lab.com/projects/misc/011.
But,when I check the schematic diagram, I found the collecotr of the Q1 was just opend and floated.
Did  anybody check this circuit? Is it O.K?

 

[audioguru2]

Hi Phil,
Welcome to our forum. ;D
The project is here: http://www.electronics-lab.com/projects/misc/011/index.html
Q1 is fine. Its base-emitter junction is connected backwards so that it has avalanche breakdown like a zener diode. When it has avalanche breakdown then it makes a lot of white noise. Its collector isn't used. ;D

 

[phil7]

Thanks audioguru.
I think your comment is very helpful for me ,thanks again.