Captret - Capacitor and Electret

[hartiberlin]

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]

Here is the samsung cap part details:

[hartiberlin]

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]

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]

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.

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.

.