Then use some wind up toy and let it bang against or shake the PCB. This way the measurements will be more consistent than tapping with pencil by hand.
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Or use something like this.
An externally hosted image should be here but it was not working when we last tested it.
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For quantitation, that seems like a really good idea.
The pencil tap is quick and dirty, but if you hear nothing, your work there is done, and you can worry about more important stuff.
I was reminded that it was 44 years ago, when I attempted to make my first 'in speaker' amplifier. It was for a set of road speakers that Alembic made for the GD roadies. They made me a set, and I still have them.
This speaker was composed of a 5'' loudspeaker in a square 15 ply birch cabinet. I tried to mount my amp inside the cabinet, but I found that it overheated. I didn't think of the vibration effects. Everyone, what about your computer speakers? A potential problem? '-)
This speaker was composed of a 5'' loudspeaker in a square 15 ply birch cabinet. I tried to mount my amp inside the cabinet, but I found that it overheated. I didn't think of the vibration effects. Everyone, what about your computer speakers? A potential problem? '-)
The vintage Siemens contact error measuring unit used a sine wave signal (3kHz iirc) which was send through the DUT, then into an amplitude detector.
You were supposed to tap the DUT (the Siemens came with a mallet!) and the detected modulation of the carrier was a measure of the vibrations in contact resistance or, in our case, the impedance (capacitance in a suitable circuit) variation. The unit has a meter and a speaker to listen to the variations. An amplitude variation of 1/1000 of the carrier could be detected. I had two of these units and gave them away...
It should not be too difficult to set up something like that.
Jan
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A.wayne asked if BLACKGATE caps were 'special'. Yes they are, (or were). They were patented, and they were made in a special way to improve their performance.
I met the designer in 1986, in Tokyo, and even saw his issued patent on the cap on his office wall.
I was loaded up with lots of samples, and I have used a few over the years. I didn't have the test equipment to measure them adequately until now, so that should be another test for my list.
The BLACKGATE caps use a 'graphite' suspended in the electrolyte (conducting) and it measurably improves performance of these caps.
However, these caps have always been very expensive, and I never could put them into a producible design. Yet, it appears that this motivated other Japanese cap manufacturers to make better 'audio' electrolytic caps, and today, we get similar performance with just the premium electrolytic caps that we buy today.
BLACKGATE caps were the first time I ever saw a break-in app for the capacitor itself. AND I think that the changes in the caps made these improvements in the cap (even measurable) cause the need for break-in in subsequent 'audio quality' electrolytic caps. So if you want to avoid 'break-in, use regular electrolytic caps. I'm serious!
I met the designer in 1986, in Tokyo, and even saw his issued patent on the cap on his office wall.
I was loaded up with lots of samples, and I have used a few over the years. I didn't have the test equipment to measure them adequately until now, so that should be another test for my list.
The BLACKGATE caps use a 'graphite' suspended in the electrolyte (conducting) and it measurably improves performance of these caps.
However, these caps have always been very expensive, and I never could put them into a producible design. Yet, it appears that this motivated other Japanese cap manufacturers to make better 'audio' electrolytic caps, and today, we get similar performance with just the premium electrolytic caps that we buy today.
BLACKGATE caps were the first time I ever saw a break-in app for the capacitor itself. AND I think that the changes in the caps made these improvements in the cap (even measurable) cause the need for break-in in subsequent 'audio quality' electrolytic caps. So if you want to avoid 'break-in, use regular electrolytic caps. I'm serious!
See electrical Dielectric strength or breakdown voltage strength of materials and gasses. A small air pocket will breakdown at a lower voltage than the solid material the cap dielectric film is made of.
If you need more details and knowledge--- it isnt pure air.... but what ever gas composition (pollution) is in the factory and that will also contain some moisture (humidity).
Tight slow and tight winding, heat annealing and careful construction, stress releiving and 100% testing gets you the most reliable part and the most consistent performance over the longest period of life time. (BTW - most audiophile caps do not go thru the annealing steps). Time is money.
About possible vibration affecting the sound.... the bipolar caps have the greatest potential for such behavour. But even a film type in a high Z circuit - such as coupling cap in a microphone preamp. Or at the front end of a high gain circuit - can be a bad position for some low quality constructed caps to be used.
As usual, what is or is not important parameter depends on the application and circuit it is used.
THx-RNMarsh
If you need more details and knowledge--- it isnt pure air.... but what ever gas composition (pollution) is in the factory and that will also contain some moisture (humidity).
Tight slow and tight winding, heat annealing and careful construction, stress releiving and 100% testing gets you the most reliable part and the most consistent performance over the longest period of life time. (BTW - most audiophile caps do not go thru the annealing steps). Time is money.
About possible vibration affecting the sound.... the bipolar caps have the greatest potential for such behavour. But even a film type in a high Z circuit - such as coupling cap in a microphone preamp. Or at the front end of a high gain circuit - can be a bad position for some low quality constructed caps to be used.
As usual, what is or is not important parameter depends on the application and circuit it is used.
THx-RNMarsh
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The world will end soon. I agree with SY. Of course Bruno lives not too far from me!
Yes you get conduction totally uninfluenced by actual wire construction. Flaws such as sulphur or oxygen, stress cracks etc. have no effect? Ohms law holds perfectly, heating of the conductors also has no influence. Right! (Sarcasm intended for those who are humor impaired.)
Scott,
I hate to break it to you but even the lifetime of the universe is finite. There is no such thing as DC. The trick is that sometimes we treat signals as DC to make analysis easier. Now when we look at a signal of 3000 hz in a 1 meter cable, do we treat it as AC or DC? The wavelength would be 3e8/3e3=3e5 meters! For 20 gauge wire we would expect about a 1% deviation in impedance vs resistance of 1% at 30,000 hz. Now would you care to discuss the difference between charge propagation and electron drift? Again there just isn't any influence from micro-diodes.
As the input voltage increases in a practical transformer you use more primary windings to avoid the core going into saturation. As saturation in most practical cores starts as a change in slope of the magnetization curve, the distortion increases the farther you go. So more windings reduce this.
I use four windings each going into a bridge, two are paralleled for each rail. However they are fed from opposite winding phases. That provides a significant reduction in the noise passed through from the transformer. A bit back I showed some measurements.
Depends on the storage conditions. Electrolytics need time to re-form the dielectric as a bit fades in storage. Some plastics absorb a bit of moisture and running them in a warmer than ambient enclosure drys them out. The audiophile grade beeswax/paper capacitors change quite a bit from warming up. It has been done measuring capacitor distortion dropping with use.
Why the peanut gallery insists you can't hear distortion 100 db down. So these capacitors will work just great in their gear.
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(Mr Simon, cheer up, judging by the picture Mr Curl posted, you'll burn the longest)
Ed again your previous posts indicate that YOU DO NOT understand how signals propagate on a transmission line. Your statement that a TDR launches a packet of charge is just plain wrong. There is no basis for a discussion.
Think for a second terminate the line in its characteristic impedance, nothing comes back the energy is 100% dissipated in the load. In your world the "charge" is destroyed - first principles - WRONG.
I can read just fine, John. I said -100dB because that is the actual figure that you wrote, i.e. "I just measured one today that measured higher than -100dB." I know you said "higher than," but that was irrelevant to my point, that being I thought it was rather disingenuous of you to give such a figure in response to Scott's -160dB figure when you were measuring a tantalum capacitor (again, apparently without any bias voltage on it).
se
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