Claimed OU circuit of Rosemary Ainslie

[TinselKoala]

@TinselKoala,

Thanks for the kind words. No, the boards is not that expensive. Only 33 Norwegian kroner (approx. 5$ US) for a single board. I needed 2 boards myself for testing but it is always cheaper to buy 25 of them than just 2. I just give away the other 23 boards since I just need two of them myself.

As I said before, people can use different values for the timing capacitors and timing variable resistor if they like. Then the board can switch other duty cycles. It is always nice to have a switch anyway when researching different circuits.

There is a board in there for you also. Just PM GotoLuc. He will be receiving 15 of the boards by the end of next month.

Groundloop.

Heh, that's pretty cheap all right. No, I don't need one, thanks.

It's good that you left room for a big heatsink for the mosfet. With a 10-ohm resistive/inductive load running at 90 percent or more ON, you might even need a small fan to protect that expensive mosfet. Mine rose very quickly to over 120 degrees C in just a couple minutes, due to the usual factors. Increasing the load to 85 ohms keeps most of the power in the load, even at longer duty cycles, so the transistor doesn't heat as much.

[Groundloop]

@TinselKoala,

The mosfet you are using has an RDSon of approx. 2 Ohm. The one I will be using
has an RDSon of 0,01 Ohm. I will also run the 555 (with different parts) at a frequency
of 100KHz and duty cycle at 50%. Then the heat sink size will be perfect for MY usage
of the board.

I will also build ONE board with the parts shown in the RA papers and test that board.

Groundloop.

[TinselKoala]

Ah, I see.

OK, my main concern here is vetting the claims of Ainslie, so I am looking at the performance of the circuit at 2.4 kHz, and with the component values she specified as used in the experiment she reported where she claims to have gotten COP>17 with a duty cycle of 3.7 percent ON--which is impossible with the published circuit. As you will see.

Her claims are quite specific as to that experiment, and that is what I am examining. 

But according to her there is wide latitude in general. The patent application says low freqs like 60-100 Hz,; she refers to 2.4 kHz as a "high" freq quite often...and she has said that most any transistor should work.

So you are planning to use some other mosfet as well? I see the data sheet for the IRFPG50 lists a Rds "on" of about 2 ohms, as you say, and the 2sk1548 is a bit higher.

What component do you intend to use that has Rds of 0.01 ohms? I don't think I could stick a piece of buswire in the transistor socket between the D and S pins and get that low.

[Groundloop]

@TinselKoala,

Sorry, I was a little off with the RDSon number.
The correct number is less than 0,004 Ohm.
STP80NF03L-04 FET N-ch 30V 80A TO220 RDSon <0,004 Ohm.
I will not go into what I'm planning to switch with this mosfet.

I will use the IRFPG50 in when I test the claimed COP>17 circuit.

Groundloop.

[TinselKoala]

Great minds think alike!
When I googled after reading above, that was one I picked as most probable, considering the package and the other components; I was surprised to see you working at such a low voltage, though. But high power anyway, that's an impressive little puppy indeed.
Good luck, whatever it is you're doing. I don't think I even want to know...