Author Topic: Captret - Capacitor and Electret (Read 321685 times)

hartiberlin · « **Reply #285 on:** January 23, 2011, 10:51:43 PM »

Have a look at this.

Samsung makes 100 uF 10 Volts Ceramic capacitor as SMD parts
with Y5V type material.

http://www.beck-elektronik.de/index.php?id=mlcc-keramikkondensator

hartiberlin · « **Reply #286 on:** January 23, 2011, 11:04:08 PM »

Here is the samsung cap part details:

hartiberlin · « **Reply #287 on:** January 23, 2011, 11:33:53 PM »

Wow,
I did another test with my 10x 100 nF cap bank
and precharged it to 10 Volts DC.

Then I heated it again and it easily went to 30 Volts DC !

Wow,
this concept has really potential !

Also I am reading in Wikipedia that the Y5V material has
a good selfcharging effect of about 2 %..
So this is probably already from converting the normal environment heat
to electricity.

This will get a really cheap thermo to electric generator concept now.

The next question will be what the efficiency will be, but this
all has to be tested.

Regards, Stefan.

.

DreamThinkBuild · « **Reply #288 on:** January 24, 2011, 12:28:08 AM »

Hi Stefan,

A hair dryer uses about 500+ watts. Do you think painting the caps flat black and using a couple infrared or small 3v laser diodes to heat them will give better efficiency?

blueplanet · « **Reply #289 on:** January 24, 2011, 12:43:01 AM »

I am not sure whether you are referring to negative temperature coefficient of capacitance. There many non-electrolytic materials capable of yielding higher capacitance when subjected to heat. Barium Titanate is one of those having negative temperature coefficient of capacitance at room temperature.

This self-compensating effect is well-known and being used in today's satellite technologies. This thing is nothing new, but I doubt if this knowledge is directly applicable to captret.

Self-compensating is not necessarily self-charging. Take a look on the following equations:

Q = C * V
dQ/dT = V * dC/dT + C * dV/dT

If Q does not change (i.e. dQ/dT=0), decreasing capacitance (i.e. negative dC/dT) means increasing voltage (i.e. positive dV/dT).

But I believe the Q does change in some situations.

Quote from: hartiberlin on January 23, 2011, 11:33:53 PM

Wow,
I did another test with my 10x 100 nF cap bank
and precharged it to 10 Volts DC.

Then I heated it again and it easily went to 30 Volts DC !

Wow,
this concept has really potential !

Also I am reading in Wikipedia that the Y5V material has
a good selfcharging effect of about 2 %..
So this is probably already from converting the normal environment heat
to electricity.

This will get a really cheap thermo to electric generator concept now.

The next question will be what the efficiency will be, but this
all has to be tested.

Regards, Stefan.

.

ibpointless2 · « **Reply #290 on:** January 24, 2011, 01:24:10 AM »

Quote from: DreamThinkBuild on January 24, 2011, 12:28:08 AM

Hi Stefan,

A hair dryer uses about 500+ watts. Do you think painting the caps flat black and using a couple infrared or small 3v laser diodes to heat them will give better efficiency?

The hair dryer is to test the concept, The capacitors will work at room temp. The Laser idea sound cool but its more of a focused energy, but only one way to find out.

hartiberlin · « **Reply #291 on:** January 24, 2011, 02:22:38 AM »

Quote from: blueplanet on January 24, 2011, 12:43:01 AM

I am not sure whether you are referring to negative temperature coefficient of capacitance. There many non-electrolytic materials capable of yielding higher capacitance when subjected to heat. Barium Titanate is one of those having negative temperature coefficient of capacitance at room temperature.

Yes, my test was with ceramic caps, not electrolytic caps.
These have a strong negative temperature coefficient of capacitance.

Quote

Self-compensating is not necessarily self-charging. Take a look on the following equations:

Q = C * V
dQ/dT = V * dC/dT + C * dV/dT

If Q does not change (i.e. dQ/dT=0), decreasing capacitance (i.e. negative dC/dT) means increasing voltage (i.e. positive dV/dT).

But I believe the Q does change in some situations.

You are right, I forgot, that the C capacitance will decrease and that is
why the voltage rises, but as the voltage goes into the energy formula as square
Energy= 0.5 x C x V^2
I guess this nonlinearity can be used to still generate power this way via
heating such caps.
I will just try it.
Regarding the laser idea, yes any heat can be used and painting
the caps black will also help.
The question is, if there are other cap materials that have even
a stronger negative temperature coefficient than Y5V dielectricum
material.

What about Tantal electrolytic caps ?

Regards, Stefan.

Ghost_Rider · « **Reply #292 on:** January 24, 2011, 03:32:12 AM »

Try placing your caps in the sun, like on a roof. Might be better than solar panels.

ibpointless2 · « **Reply #293 on:** January 24, 2011, 04:03:55 AM »

I had some 104m ceramic capacitors laying around so I tested them to see if they would pick up radiant heat energy.

I was able to get around 100mV from one cap when I touched the cap with my hand. I got around 300mV when I placed it in front of my heater. But the best part was the reading I was getting when I left it sitting in room temperature. Sitting in the room temp I got around 2mV and hooking another one in parallel gave me a little over 3mV. So even ambient heat energy can be collected, and since the ceramic caps are cheap we can make a nice collector. I would like to see how they would do in sun light, maybe I could increase the effect with a magnifying glass. Many possibilities are opening now.

So it looks like the caps are really converting heat into energy.

ibpointless2 · « **Reply #294 on:** January 24, 2011, 04:25:46 AM »

It also seems that heat is not the only thing that contributes to the power, pressure is a factor too. It seems that the ceramic capacitors can act like piezoelectric too.

Wikipedia: "Capacitors, especially ceramic capacitors, and older designs such as paper capacitors, can absorb sound waves resulting in a microphonic effect. Vibration moves the plates, causing the capacitance to vary, in turn inducing AC current. Some dielectrics also generate piezoelectricity. The resulting interference is especially problematic in audio applications, potentially causing feedback or unintended recording. In the reverse microphonic effect, the varying electric field between the capacitor plates exerts a physical force, moving them as a speaker. This can generate audible sound, but drains energy and stresses the dielectric and the electrolyte, if any.â€ http://en.wikipedia.org/wiki/Capacitor

Iâ€™ve confirmed this with my 104m ceramic capacitor by squeezing my pen against the outer case of the ceramic capacitor on a table. Just like a piezo you must tap pressure against it, just applying a constant pressure does not work.

blueplanet · « **Reply #295 on:** January 24, 2011, 04:31:47 AM »

Quote from: hartiberlin on January 24, 2011, 02:22:38 AM

You are right, I forgot, that the C capacitance will decrease and that is
why the voltage rises, but as the voltage goes into the energy formula as square
Energy= 0.5 x C x V^2
I guess this nonlinearity can be used to still generate power this way via
heating such caps.

I hope so. I fear that this energy gain has been translated into a temperature rise in a capacitor.

If this is the case, we would most likely gain thermal energy rather electrical energy. After cooling down the capacitor to room temperature (i.e. the thermal energy leaves the capacitor), we end up with nothing.

hartiberlin · « **Reply #296 on:** January 24, 2011, 12:02:14 PM »

Quote from: blueplanet on January 24, 2011, 04:31:47 AM

I hope so. I fear that this energy gain has been translated into a temperature rise in a capacitor.

If this is the case, we would most likely gain thermal energy rather electrical energy. After cooling down the capacitor to room temperature (i.e. the thermal energy leaves the capacitor), we end up with nothing.

I think you did not understand the principle.

We donÂ´t let it cool down again, it will be always heated and thus it will always convert heat energy
to electrical energy...

hartiberlin · « **Reply #297 on:** January 24, 2011, 12:04:44 PM »

@ibpointless2,
thanks for your verification.
Do you know, which dielectricum material your caps have ?

Try to get a few big ones with Y5V.

Regards, Stefan.

hartiberlin · « **Reply #298 on:** January 24, 2011, 12:41:37 PM »

If somebody has a storage scope,
please do following test:

Take also 10 x 100 nF Y5V material caps in parallel and charge them up to 10 Volts
from a DC power supply.
Then use a 100 Ohm resistor and discharge the 10x 100 nF capbank via this 100 Ohm resistor
and record the voltage pulse at the resistor with the storage scope.

Now repeat the same task, but after you have charged up the 10x 100 nF capbank
to 10 Volts, just use a hairblower to heat them up and this way charge the
capbank up to 30 Volts.
Then again use the 100 Ohm resistor and record via the storage scope
the discharge voltage curve.

Now then let us compare these 2 scopeshots.

WHich scopeshot does have more area under the voltage discharge curve ?

Theory says, the areas should be equal, but I doubt this.

Unfortunately I donÂ´t have s storage scope yet..

P.S: You can also use a 12 Volts battery to charge it up this way to 12 Volts to start with,
if you donÂ´t have a 10 Volts DC source..
Regards, Stefan.

blueplanet · « **Reply #299 on:** January 24, 2011, 06:50:35 PM »

Quote from: hartiberlin on January 24, 2011, 12:02:14 PM

I think you did not understand the principle.

We donÂ´t let it cool down again, it will be always heated and thus it will always convert heat energy
to electrical energy...

NTC capacitor is probably what you need. It may work. But as I said, this technology is actually being used in satellites.

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