Urgent Help needed to get output of ac 5v 400hz frequency and current 500ma

[james111444]

Hi,

I am in urgent need of circuit which takes 12v dc as input and outputs 5v ac with freq 400hz and current of 500ma.

can any one give some tips or help me with the circuit.

Regards
James

 

[Resqueline]

Sine or square?

 

[james111444]

Hi

Thanks for the prompt reply,its a sine wave.

Regards
James

 

[BobK]

Find a 5 Watt audio amplifier that runs at 12V with differential inputs, and wire it up as a Wien bridge oscillator. (haven't tried this, don't know if it would work or not)

bob

 

[james111444]

Hi bob,

Thank you for the reply,I should give the output voltage 5v peak,400 hz and current 500ma to LVDT. there is a time constraint to try with audio amplifier. any proven circuits would be of great help.

Regards
James

 

[Resqueline]

Is the below correctly understood?
LVDT = Linear Variable Differential Transformer. An inductive position measuring device.
Drive voltage: 5V peak = 10V peak-peak = 3.53V RMS.
Load impedance: 3.53V / 0.5A = 7.07 Ohms
Power draw: 3.53V * 0.5A = 1.77W

 

[BobK]

This is the simplest circuit I can think of to do the job. Anything else would most likely be more difficult. You are not going to find a tried and true circuit to do what you want.

Bob

 

[james111444]

Hi Resqueline,

Yes you understood correctly.It is what i want.

 

[BobK]

Thinking about this some more. I think your best bet would be to build a separate, low-power osciallator, then feed it's output into an LM384 5-watt audio amp IC. You could then use the volume control to set the output amplitude, which might be tricky otherwise.

The simplest way to make a sine wave oscillator is with an omp amp. Either a Wien bridge or a phase shift oscillator should work well.

Bob

 

[Resqueline]

Ok, so far so good. Bob has already made a good viable proposal for a solution, work with him.

 

[BobK]

Ok, so far so good. Bob has already made a good viable proposal for a solution, work with him.

Thanks, Resqueline, but please do jump in with your own suggestions, I am an amateur.

Some useful links:

http://en.wikipedia.org/wiki/Phase-shift_oscillator

http://en.wikipedia.org/wiki/Wien_bridge_oscillator

http://www.national.com/mpf/LM/LM384.html#Overview


Bob

 

[james111444]

Thank you bob, Today i worked on sine wave generator, i used XR-2206 IC for generating sine wave,it worked fine with 400hz.but i am getting very less current.i need current to be 400 to 700ma. how can i amplify it.

 

[Resqueline]

The XR2206 is an exellent choice (and you found it yourself), but didn't Bob mention earlier to amplify the sine with an LM384, and provide a link to National above??

 

[duke37]

I last worked with LVDTs fifty years ago when new fangled devices called transitors were all the rage.
I believe that you will need a signal of low distortion and with very constant amplitude since the output (distance measured) will be proportional to voltage.
If you are to work in the positive and negative region you will need a synchronous detector.

 

[OLIVE2222]

here under a link to an "An Easy Circuit For Use With LVDTs"
http://www.mikesflightdeck.com/lvdts/lvdts.html