# How do I tell if the Wien bridge oscillator I built works

I built a wien bridge oscillator. But how do I tell if it works? I am very new to building circuits. I recently
Starting making circuits on a breadboard. I have not taken any
Electronics class. I am trying to learn how to do this.

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Baluncore
2019 Award
What frequency do you expect your oscillator to generate?
Please post the circuit you used with component values.
Drag and drop it onto your next post here.

scottdave
Homework Helper
• Did you build it from some instructions?
• Do you know what frequency it is supposed to oscillate at?
• Where did you get your circuit diagram?
• Can you show the diagram?

I'm guessing you do not have an oscilloscope. If the target frequency is in the audio range (less than 15000 Hz), you could hook up a small speaker or earphones and perhaps hear the sound. You could download a music tuning app on your phone (like Panotuner or DA tuner) to find out what frequency it is. Or another useful app is from https://phyphox.org/ (Android or IOS).
Spectroid is an Android app to show frequency sound spectrum.

I followed instructions from the website "how to build wien Bridge oscillator circuit learning about electronics articles". I used two capacitors both have 470 microfarad
And two resistors both have 1000 ohms. And I used an operational amplifier. the equation I used to calculate the expected frequency is
1/2πRC. I calculate 0.3791 hertz. Does that mean you get 1 cycle every 2.64 seconds?

IMHO, you'll be lucky getting that low a frequency to work reliably at first...
In my amateur experience, albeit with '741' op-amps, Wien Bridge oscillators often refused to 'play nice'. A gross mismatch between the R vs C impedances was often the cause. Unrelated but analogous failures abound in 'flip-flop' _-_-_-_- multivibrators when RC pairings are too unbalanced, intended function swamped by 'second order' stuff...

FWIW, trouble-shooting an 'accidental' ELF oscillator can be quite the head-scratcher as an op-amp's vast low-frequency gain may out-flank you...

Try swapping RC components to raise the working frequency to mid-audio 1 kHz ~ 10 kHz range ? A take-off capacitor and a pair of \$1 headphones should suffice to check function. Or, given the capacitor, a budget multimeter on 'AC Volts'.

Get the beast working in mid-range, then work outwards by wary stages.

( I began with soldered strip-board, grabbed my first solderless breadboard, an 'S-Dec', with cries of glee. Got more done in a week using that than in previous six months. Iteration is a powerful, powerful learning tool... )

scottdave, jrmichler and anorlunda
jim hardy
Gold Member
2019 Award
Dearly Missed
I built a wien bridge oscillator. But how do I tell if it works?
I calculate 0.3791 hertz. Does that mean you get 1 cycle every 2.64 seconds?
At that low frequency you could put a capacitor and meter in series across the output.
You should see the polarity reverse every ##\frac{2.64}{2}## seconds.

Svein
berkeman
Mentor
I built a wien bridge oscillator. But how do I tell if it works? I am very new to building circuits. I recently
Starting making circuits on a breadboard. I have not taken any
Electronics class. I am trying to learn how to do this.
Since you are new to learning about electronics and wanting to keep learning more, I'd suggest looking into inexpensive simple USB-based oscilloscopes. That will give you a basic way to see what your circuits are doing, and help you to build more complicated projects in the next year or two.