# Multisim and Ultiboard

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## wien bridge oscillator

hello i'm trying to simulate a wien bridge oscillator, but havn't had any waveform produced in the oscilloscope. Does anyone know where i'm going wrong?

my file is attached.

thanks

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## Re: wien bridge oscillator

Hello,

I see 2 errors in your schematic:

- the negative supply of the opamp has a positive 20V value --> change that to -20V

- The oscilloscope second end is not connected to ground --> connect it

If you do so the schematic is correct, however the output is not what you expect. The wien bridge give an output of a few nV, you will be able to see this if you run a transient time simulation or on an oscilloscope, the agilent oscilloscope will not be able to show it because the minimum voltage per division it has is 10mV/Div.

A hint in order to make your circuit work properly, change your gain resistance R1 from 20K to 22K and you will have a good 20V swing signal that you will be able to show on either the agilent oscilloscope, any other oscilloscope instrument or the grapher of the transient time simulation.

Mahmoud Wahby

Product Marketing Engineer

NI

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## Re: wien bridge oscillator

Many thanks Mahmoud, I will give that a try.

Cheers

John

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## Re: wien bridge oscillator

How do I have to modify wien bridge to have 20khz and 50khz sine waves. opamp supply is -12 and 12 V

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## Re: wien bridge oscillator

Hi Asaka,

The resonating frequency of the wein bridge oscilator is dependenant on the RC circuits, regardless of the opamp supply.

The formula for this is F=1/(2*pi*R*C) the example above is running at nearly 1K because the R= 1.5k and C=0.1u

Regards,

Ben Clark
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## Re: wien bridge oscillator

Hi all

Can somebody please let me know how to design high frequency Wein Bridge Oscillator in Multisim using AD844?

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## Re: wien bridge oscillator

Hello,

What have you tried so far? can you attach any code?

Thanks,
Sas

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## Re: wien bridge oscillator

Hi. I've been working on using LM741 op amp to produce a 2.5kHz fo but my multisim simulation shows max 2.47kHz only and when i try to have my rin exactly half of my rf, there is no oscillation. why is that so? my gain ckt is connected on the inverting termin of the op amp and my rc ckt is connected on the non inverting terminal. Please help me can someone please email me if you guys tried to work on this? my email is: jee.freelancer03@gmail.com

i have tried to use different values of capacitors and their corresponding resistor values that i get using 1 / (2pi)(r)(c)