OK, this is the last time, I promise-still not working

[ExpAnonColin]

On the 2 points marked ground, I have a splitter with 2 100ohm resistors, one from ground and one from V+.  My oscope and DMM read 4.6V for that and 9.4 for the supply.  I have grounded the "V-".  What is wrong?  This is my third attempt.  Normally I can get these first try.  

-Colin[/img]

[Joep]

Hi Colin,

Check this site. Scroll a bit down and there is a triangle and square generator there. Your schem looks fine, maybe it is the values you use. The schem in the link has values about 10 times higher.

The frequency f = 1 / (2 x R x C)

In you schem it is around 600 Hz, is that ok?

Bye,

Joep

[puretube]

with the correct potentials applied at the right points, the schematic itself works with the depicted values!

[ExpAnonColin]

I would be able to see it on my o-scope no matter what the frequency, wouldn't I?

I've tried that other design, too, but thank you!

-Colin

[ExpAnonColin]

Changing to 22k didn't do anything...

-Colin

[puretube]

Colin: I get 1.3 kHz out of your circuit with R1=2.2k(6Vp-p TRI, 8Vp-p SQR). (130Hz with 22k).

(just breadboarded it with half a TL084 and a 9V battery)

However: my voltage-divider is 2 times 10k, not: 100ohm.

And: I did not follow the drawing exactly...
(I call pin8: " +Ub ", and pin4: " 0 ", which IS ground/minus-pole of the battery, and pins6/3: " Ub/2 ").

maybe you could redraw your schem exactly the way you hooked it up?
(including the "splitter").

b.t.w.: the scope-probe-ground should be connected to pin4 of the IC....

[puretube]

are you working with battery, or now with a bipolar P.S. ?

[ExpAnonColin]

Here's what it looks like on the breadboard:



I've tried using a 9v battery and a power supply, neither worked.

I'm getting the following voltages:
V+: 8.5
Vb: 4.2
Gnd/V0: 0v
Pin 1: 1.43
2: 7.78
3: 4.25
4: 0
5: 4.46
6: 4.26
7: 7.78
8: 8.5

Thanks for your help.

I've tried it "stock", with different "splitters", and with different values for the 22k resistor.

-Colin

[puretube]

OK, should work, if you make the "splitter/divider" 2 10k resistors instead of 100......
(i used 8.2k instead of the 9.1k, but that shouldn`t matter too much;
i put in a 250k pot with a series-resistor of 1k for the 2.2k/22k that i had suspected to be too small, and could tune it all the way down)...
Try It!

[Maneco]

Correct values:

r1 : 22k

r2 : 47k

r3 : 33k

c1 : 0.01

divider : 2 x 3k3,with 10 uf in parallel with the r that goes from virtual ground to -v

works with lm833,from 5 volts and up

[ExpAnonColin]

Maneco-I've tried .01uf for the c1, and the 10uf cap, but I'll try all of your values together.  Thanks to you both.

-Colin

[ExpAnonColin]

With those values, it still doesnt work

Pin 1-1.45
2-8.74
3-4.75
4-0
5-4.94
6-4.75
7-8.76
8-9.53

-Colin

[puretube]

tried voltage-divider with 10kohms?

[ExpAnonColin]

tried voltage-divider with 10kohms?

Yep, still works as Vref.

-Colin

[ExpAnonColin]

Sigh. (of relief)

It works.  Thank you all for your help, thank you all very very much.  The schematic I drew up works just fine, so if anyone wants to repost it anywhere without permission, feel free.

-Colin

[Jason Stout]

Do you know what the problem was?

[ExpAnonColin]

Do you know what the problem was?

I'm not totally sure... something with the R3 value being too high.

-Colin

[Robin]

Just curious, Colin ........ you say circuit works fine as drawn. Seems 100 ohm dividers would slap on an awful lot of bias current. Did you end up with 100K's (or 10K's)? What is (was) R3?

[ExpAnonColin]

10k's.  The R3 is the 9.1k resistor, I think the tolerances were messing me up.

-Colin