Ok.. I am currently working on a project in which i want to convert a DC signal to AC signal. after much review i decided to go with a bubba oscillator to just obtain a 60 hz signal. my problem is how do i go about using the 12V Dc that i have to obtain that 60hz signal. any helop would be greatly appreciated.

 

Connect the 12VDC to your oscillator.

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thank you brown out for that reply, but I dont think the problem is the connecting the supply. I recently successfully connected my circuit but then after i did so and i ran a trial simulation in Multisim i began oscillating after a few seconds and began amplifying the circuit but never stopped. it appears i might have a problem with my feedback loop and help would be greatly appreciated. also any help in deriving the specific 60 hz frequency given your choice of resistor and capacitor using the information below would be greatly appreciated.

this is the info about the bubba oscillator:
Bubba Oscillator | Free Circuit Diagram

 

The oscillator circuit needs a power supply. Use your 12VDC as its power supply.

But since you did not provide an attachment nor a link to your circuit then we are just guessing that it has a single-polarity power supply.

The Bubba oscillator from Texas Instruments uses a rail-to-rail opamp with a 0.5V bias voltage. Your circuit is probably completely different and maybe uses obsolete parts.
Just guessing since you did not provide enough information.

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Uncle $crooge

 

hey guys i am sorry i didnt put more information. i do appreciate you guys responding to my post as your hell is greatly needed and appreciated. anyways i added the multisim file so you guys can let me know where i might be going wrong with this design.

Attached Files

oscillator.zip (91.9 KB, 11 views)

 

Always willing to share my hell with friends.

__________________
You don't need a quadraphonic Blaupunkt -- you need a curve
ball.

 

Your zipped file is bad.
Why don't you post the schematic as a PNG file type?

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Uncle $crooge

 

Sorry again guys, it seems i am having more problems providing sufficient information than solving my oscillating problem. anyways i attached both the png file and a pdf file. so i hope this is much better.

Attached Thumbnails

 

Attached Files

bubba_oscillator.pdf (37.7 KB, 14 views)

 

Try 1.5M for R3. Are you telling us that this doesn't work in simulation? Of have you built this?

__________________
You don't need a quadraphonic Blaupunkt -- you need a curve
ball.

 

well it is my intention to build it. but it does not work when i ran a simulation on it . i also tried the 1.5M for R3 and that too does not give any result.

 

I got it to simulate correctly in LTSpice. I had to do 3 things to make it work:

1) Correct your VCC connection error in the far-left Amplifier

2) Change your R3 to 2 MEG ohms for sufficient gain

3) Make the 6V a rising edge. Because simulators assume all initial conditions are steady, you need some kind on stimulation to get oscillations started. In a real circuit, these conditions usually exist.

Attached Thumbnails

 

__________________
You don't need a quadraphonic Blaupunkt -- you need a curve
ball.

 

hey brownout, thanks for in information you provided, again i appreciate it very much. i corrected the VCC connection problem as well as changed the value of R3. my only concern is the 6V being a rising input. are you telling me i have to make it a square wave input or someting of that sort. and can you elaborate on your explanation a little bit more cause i did not really understand .sorry for the trouble if any.

 

The 6V does not need to be a sqaure wave. You can see in the waveform I posted that it is just a rising edge at 100ms (blue trace) and that it remains a constant 6V after that. All oscillators need something to get them started. In real circuits, that can be a switch on transient, or just random noise. Usually, something is there for starting. I've seen other oscillators that include a starting circuit, but these are rare. If you build this circuit, it will probably start correctly. But in simulations, you might need some kind of transient to make it start. Until now, I haven't simulated an oscillator, so I had to learn that too.

__________________
You don't need a quadraphonic Blaupunkt -- you need a curve
ball.

 

hey brownout, i was able to do everything except simulate the rising edge in multisim. i still ran a simulation but it begins to oscillate and then amplified to infinity so my guess is i have to use the exact conditions as you did. any suggestions on how i can make the 6 volts a rising edge on multisim.

 

I'm not familiar with multisim. What do you mean it amplified to infinity?

__________________
You don't need a quadraphonic Blaupunkt -- you need a curve
ball.