200kHz oscillator

Most benctop function generators can just about do that.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com

What kind of power? Voltage and current. I was thinking a sig. gen. and power opamp.

George H.

Generate at low level, buffer, filter, amplify the s**t out of it.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com 

I'm looking for work -- see my website!

Well... what V, I and Z were you expecting? Because it doesn't sound like much, assuming you chose the LC values intentionally.

1W at 50 ohms is 7V and 141mA, RMS. A Royer doesn't really work at extremely low Q, so let's say the minimum Q should be 3, or a parallel resonant tank of 16.7 ohms. Or 47nF and 13.3uH.

To keep it going under heavier loading, you probably want much less than that, so the Q stays above 3 or 5, say, at the highest loading.

An ungapped winding doesn't mean much, either. You need air to store energy!

And you should probably use power MOSFETs, like a pair of IRF540. No need to worry about base current, or teensy BJTs puffing off when you inevitably short it out. :-)

Tim

-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website:

Yup. 10V peak ~= 7V RMS into 50 ohms is about 1W. Which is why the function generator output amplifiers need to be beefy.

I had a look at one of the Agilent ones' output before sending it back for repair (wasn't the output section, I suspect it lost its calibration constants) .. parallel high frequency high performance op-amps IIRC.

--sp

--
Best regards,  
Spehro Pefhany

If it's resonant and produces a sine wave it isn't a Royer oscillator, but a Baxandall oscillator.

If you make the choke too inductive in a classical Baxandall oscillator it can "squeg". This only happens if you use bipolar transistors as switches, and doesn't happen if you use MOSFET switches (though start-up voltages can go rather high with a high feed inductor).

With a supply voltage of 8V you can't just connect the gate of one MOSFET t o the drain of the other - you get more than 20V between gate and source, a nd it can be even more during start-up.

The simplest MOSFET driven circuits can be difficult to get to start up nea tly - using a pair of bipolar transistors to drive the MOSFETs offers a tid y solution - see the oscillator part of the circuit at the bottom of the pa ge.

lator1.htm

If you load a Baxandall enough, the harmonic content of the output goes up a lot, and you can kill the oscillation completely. The late Tony Williams had found that a Q higher then ten didn't give you a better sine wave, and a Q less than five gave you something less than good.

100k of base polarisation doesn't sound like much.

Spice it and look at the actual currents.

Baxandall should work fine, but you do have to think about what is going on .

--
Bill Sloman, Sydney

On a sunny day (Tue, 2 May 2017 19:56:46 +0200) it happened Piotr Wyderski wrote in :

Do it the China way:

:-)

More details, please.

--
 Thanks, 
    - Win

the pcb looks like one of those cheap chinese induction heater driver, based roughly on this:

On a sunny day (4 May 2017 14:35:57 -0700) it happened Winfield Hill wrote in :

The picture comes from an email discussion I had with Bill Sloman some time ago, about what was it? Baxandal (Bill correct me). I think Bill recently posted the circuit diagram here? But anyways (looking up emails):

this sells on ebay as: (many sellers) The flat coil in my picture is for inductive cooking (discussed here long ago). I just needed some high voltage high power high frequency sine wave, so made a simple air transformer, not efficient that way, but by moving the coils apart you can control amplitude.

This is with better coupling (230 V light bulb):

The copper pipe gets warm.. Frequency is set by number of turns and C values.

It is easy to make your own:

but that one has no nice sine wave as the cores saturate...:

It will be used to power my drone via a thin RG178 (IIRC) coax, so it can stay up indefinitely with an antenna for something I want to test. I send high voltage low current up, and transform at the drone back with ringcore to 7.5 V 10A or so. I ordered 30 meters coax from Bad Seller on ebay for this, and received this:

damaged in many places, and came in 10 + 20 meters connected like this: so YMMV with China (about 50% crap ATM). I contacted Bad Seller and he assured me it would work fine like that. I gave him the first zero rating I ever gave to an ebay seller.

Anyways that project is waiting for better weather, better stuff is on order.

Does this answer any of your questions? If not, then I could draw a circuit diagram of

but I usually skip that part and I have not used spice for a long time (it is fake as you know). and nobody can read my pencil drawings anyways it seems... But it is much the same as the one at the start of this story, except I use a center tapped core, Bill will fill you in on how to name those configurations ;-)

On a sunny day (Thu, 4 May 2017 14:55:20 -0700 (PDT)) it happened Lasse Langwadt Christensen wrote in :

Yep.