Rosemary Ainslie Circuit Demonstration, June 1 2013

[profitis]

@markdansie.take zinc for that flu if it it is flu,worx evrytime for me

[poynt99]

Q1 and Q2 oscillations, how to tell them apart, how to make them continuously, who cares.

http://www.youtube.com/watch?v=8PitNm44_bE

I've been able to do this in the sim in the past (and I've posted results of it), but the present circuit Q1 will not go into osc. for some reason. I think it is due to the placement of inductances; i.e. I'm missing one. Anyway, that is not so interesting and is known. I was hoping to see the larger amplitude osc. on Q1 as you adjusted the bias, did I miss it? The amplitude seemed about the same as Q2's. When you use the FG, isn't the Q1 osc. amplitude quite a bit higher than Q2's? Also, this may not make a huge difference, but I was using a 50 Ohm in series with my DC bias supply to emulate the FG.

[Groundloop]

I've been able to do this in the sim in the past (and I've posted results of it), but the present circuit Q1 will not go into osc. for some reason. I think it is due to the placement of inductances; i.e. I'm missing one. Anyway, that is not so interesting and is known. I was hoping to see the larger amplitude osc. on Q1 as you adjusted the bias, did I miss it? The amplitude seemed about the same as Q2's. When you use the FG, isn't the Q1 osc. amplitude quite a bit higher than Q2's? Also, this may not make a huge difference, but I was using a 50 Ohm in series with my DC bias supply to emulate the FG.

.99,

If you want Q1 oscillations, then put a 100nF capacitor over Q1  drain/source. The Q2 (and three other MOSFETS) do
more easily go into oscillation because of the paralleled drain/source capacitance. Also, as you said, it helps with
long wires (or simulated inductance) on the MOSFET.

GL.

[poynt99]

Hi GL.

The extra capacitance isn't required. I have several different simulation versions of this circuit, and I've been able to demonstrate Q1 oscillation in the past as mentioned, without adding any extra capacitance. I''m fairly certain I'm missing some inductance is all, but this is territory I've already been through and it does not really interest me nor pertain so much to the test results and claims.

TK's insight into an incorrect positioning of the Fig. 3 CSR probe seems a very real possibility now that I've seen the recent demo and how they had the CSR probe connected. Not only that and more importantly, the demo on Saturday clearly showed that it is not possible to reproduce the Fig. 3 scope shot with a functioning Q1 and "proper" probe placement.

[poynt99]

S. Weir,

Please contact me. I think we have much to discuss.

poynt99 @ overunityresearch.com