Generating a 100KHz sine current for test?

Generating a 50KHz sine current for test?

Hello,

I need to generate a 50KHz sine current of peak = anywhere between 350mA and 1A
(sorry the title wrongly says "100KHz")

Is this an OK way of doing it?
(as attached)

Is there a simpler way of generating this approx 50KHz sine?


(.....the resistor on the RHS is the resistor in the test circuit, into which the 100KHz will be injected.)

Your circuit is horribly complicated. A single opamp could make a Wein-bridge oscillator to make a nice 50KHz sine wave.

E=IR so to get 1A through 0.39Ω requires 0.39V. The power is P=E^2/R = 0.15W

My HP signal generator would easily put 10V into 50Ω = 10*10/50 = 2W, so I would use a small toroid transformer with a turns ratio of ~10:1 between the generator and the resistor...

Your gradually giving your circuit away.
Acouple of ideas:
1- the duty cycle should be as close to 50% as you can get it. Right now I don't think the 555 is quite 50%
2- You can eliminate the second supply. The capacitors ac couple it to the load. Kind of like the exciter circuit in the attachment from your other post. Cost reduction....

**broken link removed**

You need to run the sim at the proper frequency to get the effect of the resonant circuit.

If you post your spice .asc file we can all run it without drawing it all up.

Breaking it up into pieces is confusing everyone because they can't figure out what you are trying to do.

heres the sim

Im not too bothered by it not being absolutley sine due to non 50% duty


.....the circuit's too difficult to tune to resonance, and near resonance , its very over sensitive, so i deliberately use it off resonance

Need to post the .asc file. It is the one in ltspice with the little transistor next to it.

Thanks for requesting it.............here it is...

Now we got it!

The circuit is resonate at about 54 Khz. Maybe because we didn't calculate the inductance of the twisted pair.
So I modified it by changing the cap slightly on the 555 and eliminating the power supply so the sim would run faster. If you scope the voltage at the top of the inductor it will be quite high and a nice sign wave due to the resonance. Works good.

thanks, yes theres 250V peak at the inductor.

Do you think this is a good way to get the sine wave?

i keep reading about wein bridges, but all articles say they are problematic and unstable......?

For your system this is the way.

Here is a nice write up.

https://www.electro-tech-online.com/custompdfs/2013/01/Wireless20Power20Transmission.pdf

Thanks, thats about wireless power transmission......from coil, then through the ether...to other coil

Ive read quite a bit about that...............incidentally , its not what my company do............my company (or rather , the one i work for) uses a twisted pair cable as the "primary", and prizes apart a twist of twisted-pair, so that they can hook in a resonant inductive coupler, and then couple power out of the twisted pair like that....to light leds.............they can hang 250W's woth of led lamps off of a 12 foot piece of twisted pair.........from my point of view, thats pretty amazing.

I have searched and searched the web , and i have found *not one other company in the world* , who is doing it..thats a lie.........i did find one other.............but that was it.........................and i suspect that theyre the same as us, because i think the investor has hived the technology off to the other company, so as to get more minds working on it.


The company that i work for cannot be found on the web, unless you type in a specific search term...................and its kind of weird, because that search term isnt particularly descriptive about the technology that we use.

Could be. I don't know about your coupling method so I can't comment.

Either way you should make your receiver resonant at the same frequency as the transmitter to get the maximum output.

If you want to get FCC approval in the US you should move the frequency into the band suggested in the article. Say 170 Khz.

That would also make your caps smaller.

The transmitter is the twited pair....or rather , the bit of the twisted pair that they pulled open to hook in the coupler.........the twisted pair is driven by a 50KHz current source.

Call me a complete Schmuck for thinking that this is quite revolutionary?

Maybe they use special high permeability coupling ferrites?

Yes, I think if there is magic it is in the coupling of the 2 lines to each other. Then it is more like a transformer than a transmitter.

by "2 lines", i take it you mean the go and return of the twisted pair?

by the way, it doesnt have to be a twisted pair, it can just be a loop of wire, but they make it twisted pair so it doesnt radiate so much switching harmonics of the 50KHz power source

Yes, I thought from your other post that both the transmitter and receiver both passed thru a "core". This would make the coupling better than air. I guess it depends on your application. There must be some reason for doing it the way your are otherwise you could just plug the LEDs into a power supply.
I used the one I posted because the battery in my wireless mouse kept going dead because I forget to turn it off. So I built the transmitter into a mouse pad and put the receiver on the bottom of my mouse with a rechargeable battery so it is still wireless but the battery lasts.

...if you plug them in, then you need a connector, whereby metal gets pressed against metal from each mating surface.........and if the mating surfaces have access to each other, then so too does any moisture in the air in which the mating surfaces reside.

......thats the big deal...............i cant think of many applications needing this, but maybe the lights on a ship where wave splashes are coming in through the windows, etc etc etc

But how do you get the twisted pair out of the box with you electronics in it?

Yes i see what youre saying, there is a metal to metal contact at that point, but its only at that point, and not at the point of every luminaire...............but yes i see your point, but the idea is just to keep the 50khz current source tucked away in the dry.........i suppose anyway..........

..i dont really know, and since theres only one company in the world doing it, i guess it'll be a pretty big secret.............so i guess i'll never know.