Yes, very nice indeed.

But.... with only one Q2 you have, of course, only 1/4 the total Ciss capacitance, so your oscillation frequency (the fundamental or "base" frequency, thanks PW) will likely be a bit higher than Ainslie's.

Also... with both your Q1 and Q2 on the same heatsink, it will be more difficult for you to monitor the mosfet temperatures to see, for example, that in the high heat mode of the conditions leading up to the Figure 3 failure, the Q1 mosfet heats rapidly and the Q2 heats much less.

What kind of container are you going to use when you "bring water to boil"? And ..... How Are You Going To Demonstrate that your mosfets are still completely functional after you reproduce the Figure 3 scopeshot?   


Your pulse generator is worth more than my house. Or at least it was when it was new. And your scope is worth more than my car and my housemate's car combined.

ETA: I see that the 8161A has an output of -5 v to +5 v. Or is that an 8160A? How do you intend to manage the offset range that Ainslie's circuit requires?

You've got Ainslie all hot and excited now, "poynty poynt". But tell me something, please..... not to detract from your present work of course but other than your use of fewer mosfets and a digital scope, just how exactly is your present construction different from the work I did with Tar Baby over the past two years? What will you be able to do with it that I haven't already done, and demonstrated on a video? Please tell me, so I can try to keep up. I have Tar Baby set up on my bench right now, just waiting for something new to do with it.

Oh.... yes.... I see now. Your batteries are 7 A-H and mine are only 5. And you are using a pulse generator instead of a function generator. Well, I do have the DP-101.....

Quote from: TinselKoala on June 19, 2013, 12:30:42 AM
ETA: I see that the 8161A has an output of -5 v to +5 v. Or is that an 8160A? How do you intend to manage the offset range that Ainslie's circuit requires?

I have a few 8160A's. The output spec is into 50 Ohms, so the output is actually +/- 10V.

Quote from: poynt99 on June 19, 2013, 08:55:25 AM
I have a few 8160A's. The output spec is into 50 Ohms, so the output is actually +/- 10V.

That's good..... you may need them. Because it is possible (just barely) to experience a failure mode involving the Q2(s) that will pop the final output stage of your generator. Mark E has warned about this in his circuit analysis, and both Ainslie and I have experienced it. I was able to repair the discrete components in the output of my F43, and Ainslie simply replaced the cheapo FG that she was using. I've not seen the inside of an 8160A but other HP instruments of that vintage are.... shall we say..... rather tightly constructed inside.

Have you managed the negative-going integral yet?

(Scopeshot below is unrelated to the failure mode)

With a 38V supply, I am not too concerned, as the output devices should tolerate a dead short of Q2 in such case. However, I am concerned to go higher, and therefore plan on building an external drive to buffer the 8160A.