Gentlemen, I suggest that we are getting OT; the original intent was to post MIRINGU's query, and to provide assistance as necessary/possible.

If someone wishes to double-check my simulation, contructive criticisms will be most welcomed. Please see the attached.

I've created a couple of copies of the LM3909 replacement circuits that I suggested in the beginning, inserted with the schematic he supplied, with corrections that were necessary.

Perhaps my model is not correct. Some of you might be able to find the fault in it.

But I'm at wit's end here. I just don't see this thing working.

Show me wrong.

(Linear Technology's Spice format attachment)

 

OK, here is the low voltage LED version.

Did you try it?
The datasheet for the LMC555 and TLC555 show that its output current is only 1.5mA going low when its supply is only 3V and is less when the 3V battery runs down to 2V. The LED would be very dim.
Its output low current is 100mA when its supply is 15V.

 

Gentlemen, I suggest that we are getting OT; the original intent was to post MIRINGU's query, and to provide assistance as necessary/possible.

If someone wishes to double-check my simulation, contructive criticisms will be most welcomed. Please see the attached.

I've created a couple of copies of the LM3909 replacement circuits that I suggested in the beginning, inserted with the schematic he supplied, with corrections that were necessary.

Perhaps my model is not correct. Some of you might be able to find the fault in it.

But I'm at wit's end here. I just don't see this thing working.

Show me wrong.

(Linear Technology's Spice format attachment)

The biggest problem I see is that you have nodes in the two circuits shorted together. When you give a node a name (or a number), that node will connect to any other point in the schematic with the same name.
I removed the node numbers, then the bottom circuit oscillated. I changed the return on R21 to Vcc, and they appeared to both oscillate at exactly the same frequency. I changed the source resistance of Vcc to zero, and the top circuit stopped oscillating. I added the LED in the top circuit and removed R21, so both circuits were identical except for the timing cap. Then they both oscillated, both with very narrow negative pulses going to the NAND gate you have on the left. I wonder if that was the intent?
I get 90V pulses on the output!

 

Did you try it?
The datasheet for the LMC555 and TLC555 show that its output current is only 1.5mA going low when its supply is only 3V and is less when the 3V battery runs down to 2V. The LED would be very dim.
Its output low current is 100mA when its supply is 15V.

No, I haven't. A valid point. I will be doing something with it, as it has peaked my interest.

I was doing this as a reply to the OP showing how I would do it. If it doesn't work as is I will be modifying it to make it work.

I need to find out if a RadioShack CMOS 555 is the same thing or not, I'll get back with you on this.

 

The biggest problem I see is that you have nodes in the two circuits shorted together. When you give a node a name (or a number), that node will connect to any other point in the schematic with the same name.

You mean the Vcc connections?
They were supposed to all be connected together. That's how they were wired in the schematic that Miringu originally posted (after correcting the "hop" to a connection, that is.)

I removed the node numbers, then the bottom circuit oscillated. I changed the return on R21 to Vcc, and they appeared to both oscillate at exactly the same frequency.

OK. In Miringu's schematic, R21 connects to pin 8 and ground - actually, it's a pot and a series resistor.

I changed the source resistance of Vcc to zero, and the top circuit stopped oscillating. I added the LED in the top circuit and removed R21, so both circuits were identical except for the timing cap. Then they both oscillated, both with very narrow negative pulses going to the NAND gate you have on the left. I wonder if that was the intent?

I have an idea that it's SUPPOSED to make sounds like a cricket chirping; the lower circuit basically being the enable portion, and the upper portion producing a relatively high-frequency series of pulses.

I get 90V pulses on the output!

Got quite a kick out of that inductor, eh? Well, LTSpice didn't have a speaker model, so I just threw in an arbitrary number for a speaker coil.

 

hi pin 8 is connected to R2 not R21 then it's grounded.
and it should produce evenly spaced beeps ie the aim of the project is used as meditative tool

 

A thousand pardons, SgtWookie. I just looked at your schematic again and realized that your pin numbers are comments, not node numbers. When I initially saw both circuits oscillating at the same frequency, I jumped to the conclusion that the two circuits had some common nodes, and mistakenly blamed it on the pin numbers. I'm pretty sure the actual reason was the 1 ohm resistance of Vcc.
I know R21 was connected to ground. I was just playing around, trying to get both circuits to oscillate, so I tried connecting it to Vcc.

 

hi pin 8 is connected to R2 not R21 then it's grounded.
and it should produce evenly spaced beeps ie the aim of the project is used as meditative tool

In the simulation that I put together, your R1 and R2 were combined into R21. LTSpice doesn't support potentiometers, but that's not a problem; you can simply vary the value of a fixed resistor between simulation runs.

Still, I couldn't get the upper circuit to oscillate even when I increased R21 to double the value of your combined R1/R2.

 

A thousand pardons, SgtWookie. I just looked at your schematic again and realized that your pin numbers are comments, not node numbers.

That makes sense, then. That was an easy mistake to make. I suppose I should have qualified the numbers with "Pin n" to more clearly illustrate that they were comments. Their only purpose was to document where the pins of the equivalent LM3909 IC were supposed to be.

When I initially saw both circuits oscillating at the same frequency, I jumped to the conclusion that the two circuits had some common nodes, and mistakenly blamed it on the pin numbers. I'm pretty sure the actual reason was the 1 ohm resistance of Vcc.

Well, the LM3909 was really designed to be run from batteries, which do have internal resistance. Precisely how much, I don't know offhand - it would vary considerably with the size, chemistry and depletion level of the battery. Rser=1 is a completely arbitrary value. However, I felt that an arbitrary value of 1 Ohm would be far more realistic than Rser=0.

I know R21 was connected to ground. I was just playing around, trying to get both circuits to oscillate, so I tried connecting it to Vcc.

That was apparently a good guess.

But there are obviously still problems with the circuit as Miringu has drawn it.

Either there are still mistakes in his transcription of the circuit diagram, or the original schematic is faulty. There's a lot of the latter that's been published.

 

Well, the LM3909 was really designed to be run from batteries, which do have internal resistance. Precisely how much, I don't know offhand - it would vary considerably with the size, chemistry and depletion level of the battery. Rser=1 is a completely arbitrary value. However, I felt that an arbitrary value of 1 Ohm would be far more realistic than Rser=0.

As you undoubtedly know, a big electrolytic cap (100uF?) in parallel with a 100nF cap will help solve that problem.

 

As you undoubtedly know, a big electrolytic cap 100uF?) in parallel with a 100nF cap will help solve that problem.

Right-o

I just realized I missed putting in C3 from Vcc to ground - even though it's only 0.04uF, it would help to suppress the transients a bit; not much, but a bit.

I still think that Miringu either left things out, or the original schematic is just plain no good.

 

Right-o

I just realized I missed putting in C3 from Vcc to ground - even though it's only 0.04uF, it would help to suppress the transients a bit; not much, but a bit.

I still think that Miringu either left things out, or the original schematic is just plain no good.

No am still following and i appreciate very much for your concern n help.i've learnt something.
But if the cct wouldn't work........... may be i'll come back with another thought.
but i'll contercheck the cct for any mistakes done if any.
Thanks alot

 

Thanks,
since am not familiar with simulation i was "guessing" if could be compared like this ,
LM3909 -- 555 timer
For IC1
2 - 3
4 - 1
5 - 4,8 together
8 - connect 2,6 together

For IC2
2 - 7
4 - 1
5 - 4,8 together
6 - 3
8 - 2,6 together
the others i ignored,can this "guess"funtion when simulated?

I was thinking about replacing with 555 timer as in the schematic below.But for pontentiometer i used varistor athough it shd not be there.
when i tried to simulate it showed some graphs but i don't know if its working .
I used LTSpice to draw the cct.

 

I was thinking about replacing with 555 timer as in the schematic below.But for pontentiometer i used varistor athough it shd not be there.
when i tried to simulate it showed some graphs but i don't know if its working .
I used LTSpice to draw the cct.

That circuit won't work.
Below is a circuit that I simulated, and also listened to (as a WAV file). It produces chirps. You can play with the timing components (R1, R2, R4, R5, C4, C7) to get the sound you want.