Electronic Siren

[ramussons]

I remember building a 2 Transistor Siren - Not a 2 tone version, but one that ascends in pitch to a max, and then descends to a very low frequency.
This was in the 70's, from a circuit in Popular Electronics (if I recollect correctly). I have gone through the available archives of PE, but not been able to track it down.
The circuit had 2 PNP transistors, one driving a speaker directly.

Does anyone recollect this piece?
Thanks.

 

[Bluejets]

Check talkingelectronics in the first section on 200 transistor circuits (1-100)
Scroll down to get to a list of projects and you'll find one under "siren".
Cheers

http://www.talkingelectronics.com/te_interactive_index.html

 

[ramussons]

Thank you.