BBC ON THIS DAY | 7 | 1977: Queen celebrates Silver Jubilee
Otherwise I'm so beyond confused I can't keep track of the exchange. Well, except the *wonderful* level of animosity from all parties. :/
https://www.theguardian.com/music/2012/apr/29/sex-pistols-queen-jubilee-boat
The parade was two days later.
God save the queen
The f...
They made you a moron
A potential H bomb
Establishment moronic behaviour.... https://images.991.com/large_image/Sex+Pistols+Jubilee-356361.jpg
The way I tell which is the outside foil comes from cap mfr when I asked them --- is ---
If you can measure capacitance...... place the tubular film cap inside a metal tube. The C from one lead to the metal tube will be highest with the lead which is attached to the out side foil.
Done. Simple and works without a lot of circuitry (not counting the cap tester).
THx-RNMarsh
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Too noisy especially at low gains. 5nv at a gain of 5 should be achievable with a 389 pair and the THAT 1580, it does require some DIY work though.
It does remove the output common mode which is a separate issue. I have a solution for that too, I think PMA posted a version it awhile back (a simple FET in-amp with only a FET pair and a dual op-amp). Connect two of those like that late figure on the BB datasheet (I wonder where that came from).
http://www.waynekirkwood.com/images..._Noise_Wurcer_Kitchin_EDN_October_13_1982.pdf
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What would a jfet input opa1632 bring to the table, performance wise? I can't figure out any advantage, except perhaps a better behaviour with ingress EMI, and even that would be at best marginal.
If you have a fully differential amp like the BT, and you want to use a differential servo, then a JFET-OPA1632 would fit the bill, not ?
Patrick
Patrick
I did some tests a few weeks ago and posted the results up here somewhere. Smacked the hell out of the caps and the 110k bias resistors. I think high value R's might be a bigger problem than electrolytic caps - still to complete the tests to verify though.
Nice practical test set up BTW.
I know you also need a CM servo.
But then ordinary opamp such as OPA1641 will do for that job.
I also know you can use a dual opamp to make up the diff servo.
But a JFET-input OPA1632 would be much simpler.
Patrick
But then ordinary opamp such as OPA1641 will do for that job.
I also know you can use a dual opamp to make up the diff servo.
But a JFET-input OPA1632 would be much simpler.
Patrick
an example... to find the ground side or outside foil-lead -----get some tin/alum-foil from the kitchen and wrap around body of cap/DUT:
I'll let the pictures do the talking.
THx-RNMarsh
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QUOTE=gpapag;5046427]Thank you Richard
George[/QUOTE]
If one is careful to zero out the c between leads and not move the leads more than a fraction of an inch during tests, there is a distinct different. Notice, my meter has the zero feature. And don't have the foil go over/past the cap ends.
-Richard
George[/QUOTE]
If one is careful to zero out the c between leads and not move the leads more than a fraction of an inch during tests, there is a distinct different. Notice, my meter has the zero feature. And don't have the foil go over/past the cap ends.
-Richard
If you are careful in c measurement, it would be the right lead which is the outer foil.
In a few circuit applications, one could also use copper foil or tin and solder a wire to it and ground it... for a shield.
-Richard
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Dug out the Agilent LCR meter with zeroing feature (they call it "Null" , it's the keypad at bottom right) and trimmed the tin foil. Same IAR WONDER-CAP 8.0 uF 200V capacitor.
260.1 pF foil to cap right
264.2 pF foil to cap left
images below. BTW waving the leads around a few inches, changed the displayed capacitance by 1-4 pF.
260.1 pF foil to cap right
264.2 pF foil to cap left
images below. BTW waving the leads around a few inches, changed the displayed capacitance by 1-4 pF.
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