LCR

It all depends on what you are trying to do...

Let us know why you want to put in this signal and into what then maybe we can suggest a solution?

John.

It's a simple circuit. We have the AC voltage source, a big ohmic resistor of 1 GΩ in series and a gap. Then I will put a specimen in the gap also in series which will have smaller resistance of some MΩ. The characteristics of the AC signal is as I wrote above. When the sample is stacked in the gap and the loop is closed, then all the voltage will drop in the big R, so I will know with this method that the electrical loop is closed.

You can not use DC voltage because the specimen will stick only in one electrode.

I'd build a Wien bridge oscillator, plenty of circuits on the web....

why a wien bridge oscillator? What I will gain from this?

??? If you build one it will provide the the 50khz 2v p to p signal you wanted !!!
It will be quick simple and cheap to build....

I searched in the internet for the Wien Bridge Oscillator. It's really interesting how simple it is... but as I found it's only for low frequencies (I saw an application with 20 kHz frequency). In higher frequencies there is a distortion. So I need something more stable, and controllable. If I am wrong, please correct me as I am not expert but amateur ... but thank you a lot for the answers.

They usually go upto 20kh.... 'cos that's the top of the audio band... I don't think there would be much trouble taking it up to 50khz. The amplitude stability can be troublesome, they often use a small filament bulb or thermistor in the feedback loop.

I built one years ago..I think it only used 2 or 3 transistors... worked fine. Dunno where it is now...

It's a nice useful project for an amateur.

Del

I know this is the wimps way out but you end up with something which will be useful in the future. Cost your time accurately.

http://search.ebay.co.uk/search/search.dll?from=R40&_trksid=m37&satitle=function+generator

so I suppose you suggest function generator than the other devices...

Thanks

This is not my field, but I've used 555 timers for this kind of thing. Others could better tell you if you can get close enough to a true sine wave (via filtering caps/inductor) for your purposes. They are so cheap and plentiful, that just playing around might be time well spent. Check the input and output sides of your resistor with a scope, and see if you're getting what you want. Part of having a lab is getting to play around, true?

However, if I had the budget to buy a function generator, I would jump at the chance, especially in a lab setting.

Thank you for the answer...

I can not exactly play around in my lab... my supervisor wants some answers from me if we can use the above devices or we have to buy a new one...

Hi Brintakis,

The 4284A should be able to provide the 2V p-p at 50kHz. Read the performance test section to find out which BNC it will come from. I think it's the current low, but not being at work I can't look at it now, and am not sure. If you want the voltage to be accurate, you will have to measure it with a scope or meter. There is a particular accessory made to check the output voltage that has one BNC output. That would be handy, but not essential. It sounds as though you need some more equipment in your lab. Good luck!

Regards,

S

Hello,

Pls check there is provision in LCR meter it self to vary the AC V in rms volts. convert equivilent value required for 2vPP and you can apply it across the DUT (Device Under test)

get back to me if you have any difficulty on bgkmurthy@gmail.com

KM