neutral problem in circuit DC circuit

[Arrowspace]

I have attache my circuit in post, I am using this circuit for providing sin wave to my AC circuit, but getting problem with neutral from where I can provide neutral in my circuit attached in post.

 

[BradtheRad]

The ground icons are connected to the node between your positive and negative supplies.

 

[Arrowspace]

do you mean that I can connect neutral with ground of circuit

 

[Audioguru]

An electronic circuit like your oscillator does not have a neutral. An electrical circuit has live, neutral and ground wiring.
You should learn that your circuit is wrong to be a Wien Bridge oscillator:
1) R1 and R3 must have the same value.
2) The gain must be a little more than 3 times.
3) An automatic level control circuit must be added so that the output level does not keep rising until the opamp produces clipping.

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Sine wave, AC circuit and Neutral?? Are you trying to make an inverter with a sinewave output? This way makes a heater that wastes a LOT of power from the battery.
But you could use a comparator to compare this sinewave (when it has its level stabilized) with a high frequency triangle wave and the output of the comparator will be Pulse Width Modulation making an efficient inverter.

 

[Arrowspace]

Thanks Audioguru , I am looking for 7.5Khz frequency I am going to put this sin wave to my LVDT sensor , which work on 7.5Khz with 10V rms. I need only sin wave.

 

[Audioguru]

I do not know if an LVDT sensor cares about distortion but your extremely simple circuit will produce a clipped sinewave. Usually a Jfet is used to control the amplitude of the sinewave but in "the good old days" we used a light bulb which caused the sinewave level to bounce before settling.

 

[Arrowspace]

can you provide me circuit

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How can I provide 10V rms to my circuit with frequency 7.5khz

 

[Audioguru]

Simply look up Wien Bridge oscilllator in Google.
But an opamp cannot drive an impedance less than about 2k ohms but some can drive 600 ohms.

10V RMS is 28.3V peak-to peak so the amplifier will need a supply that is about plus and minus 32V.
I suspect that you need an audio power amplifier to drive your coil. The Wien Bridge oscillator can use an ordinary opamp and it drives the audio power amplifier.

 

[Arrowspace]

Thanks Audioguru , But my problem is still their, can I connect output of opamp with one end of coil and other end of coil to ground of my digital circuit. Can negative sin wave damage my circuit ?

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ok, is their any neutral in single phase or can I earth second end of my coil .

 

[Audioguru]

I think an opamp does not have enough power to feed your coil. The coil is probably low impedance and needs to be fed from an audio power amplifier that is driven from the oscillator.

Your Wien Bridge oscillator uses a positive and negative supply which causes its output to swing positive and negative. It can drive the input of an audio power amplifier that also uses a positive and negative supply.
The circuit has no neutral and does not need an earth ground.

The coil that you feed a sinewave to can be fed from one end with the other end at common (some people call it common or circuit ground) or the coil can be fed push-pull as shown on your schematic from the outputs of a bridged audio power amplifier.

 

[Arrowspace]

Is that correct as shown in pic

 

[Audioguru]

Multisim (<text> <text> <text>)? I wish it had straight lines (look at the line connecting to pin 3 on the opamp), no grid lines all over it and a white background.

Your simple Wien Bridge oscillator can drive a coil with an impedance not less than about 2k ohms.
Its frequency will be about 533Hz and its output level will keep rising until the opamp produces clipping as I showed.

 

[Arrowspace]

why it's 533Hz i simulated on software it's around 5kHz


My question is that, can I connect coil like that as shown in pic

 

[Audioguru]

Your simulation software is WRONG.
The first circuit I posted uses 10.2k resistors almost the same as your 10k resistors but it uses 3nF capacitors that have a value 10 times less than your 30nF capacitors. Its frequency is shown to be 5.2kHz. If the 3nF capacitors are 30nF like you have then its frequency will be 520Hz.

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You did not provide the minimum impedance of the coil so it might be shorting the output of the opamp to circuit ground if it is less than about 2k ohms. If it is 2k ohms or more then the opamp output will swing up to about +12V to +14V and produce clipping, then it will swing down to about -12V to -14V and also produce clipping.

 

[Arrowspace]

Ok my coil resistance is 3K

 

[Audioguru]

The clipping produced by the opamp creates harmonics. Will the harmonics mess up the results of the circuit?

 

[Arrowspace]

yes , can you tell how can I remove clipping, where I have to add Jfet in circuit, how to configure it.

 

[Surender Reddy]

Hi,



You need to isolate the circuit why don't you try with isolater.

 

[FvM]

The clipping produced by the opamp creates harmonics. Will the harmonics mess up the results of the circuit?

yes , can you tell how can I remove clipping, where I have to add Jfet in circuit, how to configure it.

Why would the clipped voltage affect LVDT operation? I don't believe that this is the case. The answer might depend on the details of synchronous rectifier used as receiver. Level stabilisation would be wanted however, because the drive voltage acts as scaling factor for the displacement measurement.

You need to isolate the circuit why don't you try with isolater.

Why, particularly? And what do you mean with an "isolater"?

 

[Audioguru]

Here is a Wien Bridge oscillator with a Jfet controlling the output level: