ok i messed with a few settings and swapped my cmos to the led and it works. I found that you cna get different tone freq with swapping the 10K pot at R2 for a 1K and then mess with the different adjustments. imm work on the amplified signal tomorrow when i get soem 1/2 watt 1000 ohm resistors. all I have are 1/8th and 1/4

 

So is it about where you want it frequency wise? One of the reasons I went with the convoluted design, so when the LED was dim the frequency would be low, and visa versa.

If you get a chance I'd like to see your final design.

 

can it be tweeked to get the frequency a little lower. Ill get the video made of it on here later tonight after I get home from class.

 

If you do not power the opamp then it won't have an output signal.
A Cmos 555 does not have enough output current to drive the speaker. A real 555 has much more output current.

 

Welcome back stranger.

You might want to read the whole thread to put it into context, a CMOS 555 is as real as it gets, and not even a conventional 555 can directly drive a speaker. Assuming no power is applied to the op amp is kind of a reach too, but then I don't see you draw many schematics. Critics always have an easier job, takes less time to do their job.

 

Well, he said the circuit worked when he replaced the wimpy Cmos 555 with a real and powerful 555 like on your schematic, Bill.

He asked if he should connect the power pins of his opamp so I answered him.

I am looking for the circuit that has a 10k pot for R2 and another circuit that has 22.4V across a 1k resistor (1/2W).

 

At which point the magic smoke probably escapes, given that 555s are around 15V max (18V for CMOS). Try looking at post #15. I don't recall him asking for a siren, just a low throb that was audible.

 

I found the 10k pot that is used for one of the two R2 pots.
I don't see a Cmos 555 on any schematic in this thread.
I don't see a supply voltage shown for any schematic in this thread.
He is worried about using a 1/8W or 1/4W 1k resistor but why does he need a 1/2W resistor?

 

Try post #18.

Are you trying to be obnoxious?

Do the math, and remember to derate by 50%.

 

the circuit is working great. I swapped my 2 555. put the cmos I have driving the Led and the other is on the speaker side. i asked about the power on the op amp due to the fact that the speaker still works when there is no power to it and if only the ground or vcc is connected. The 1/2 watt was a few schematics to boost the output of the 555 for the speaker to make it Louder. its all working off a 9v batt