Accurate Measurements on pulsed system's harder than you think.

[tinman]

TK
Try an inductor with a core.
I think the results will be better and more evident.

P.S--forgot to ask--no power measurements mentioned on the video?.

Brad

[seychelles]

IT SEEMS THAT WE ARE LOOKING AT REFLECTIVE POWER..

[picowatt]

Tinman,

Surely you are not serious...


Incandescent bulbs have a very large positive temperature coefficient.  As such, they present very non-linear I versus V behavior. 

Incandescent bulbs tend to regulate the current flowing thru them.  As more voltage is applied to the bulb and it attempts to draw more current, the temperature of the filament increases, which increases the filaments resistance, which reduces the current flowing thru it.  This inherent behavior has been used for many years in unique applications such as current limiters and sine wave oscillator AGC circuits.

Incandescent bulb filaments have thermal mass and, therefore, thermal inertia.  Because of this thermal inertia, the temperature of the filament, and therefore its resistance, will be different for applied voltages having different frequency, duty cycle, and peak voltage values, even if the average value of those applied voltages are identical.

Incandescent bulbs are very inefficient emitters of visible light.  The bulk of their emissions is in the far infrared and their emission bandwidth (spectrum) is highly dependent on the temperature of the filament.  The limited spectral response of a typical solar cell is not going to respond to the long wavelength IR which represents the bulk of the bulb's emissions. 


Lesson to be learned, always use a low temperature coefficient, non-inductive resistor for your CVR...

PW

[tinman]

Tinman,

Surely you are not serious...


Incandescent bulbs have a very large positive temperature coefficient.  As such, they present very non-linear I versus V behavior. 

  This inherent behavior has been used for many years in unique applications such as current limiters and sine wave oscillator AGC circuits.

Incandescent bulb filaments have thermal mass and, therefore, thermal inertia.  Because of this thermal inertia, the temperature of the filament, and therefore its resistance, will be different for applied voltages having different frequency, duty cycle, and peak voltage values, even if the average value of those applied voltages are identical.




Lesson to be learned, always use a low temperature coefficient, non-inductive resistor for your CVR...

PW

I am very serious PW,and i think you missed the boat here some where.
Did you watch the first two video's ? ,do you know what this thread is all about.

Incandescent bulbs tend to regulate the current flowing thru them.  As more voltage is applied to the bulb and it attempts to draw more current, the temperature of the filament increases, which increases the filaments resistance, which reduces the current flowing thru it.

Please post a short video here showing us how you can raise the voltage across an incandescent bulb without the current also rising. Yes,the resistances rises as the element rises in temperature,but in order to gain a temperature rise,the current flowing through that bulb must increase,and as the temperature rises,so will the visible light output.

Incandescent bulbs are very inefficient emitters of visible light.  The bulk of their emissions is in the far infrared and their emission bandwidth (spectrum) is highly dependent on the temperature of the filament.  The limited spectral response of a typical solar cell is not going to respond to the long wavelength IR which represents the bulk of the bulb's emissions.

This is telling me that you have not watched the first video,where there was no solar cell being used,and the rise and fall of visible light was very apparent. Once again,the only way to increase the visible light output of an incandescent bulb is to increase the current flowing through it-->which will increase the voltage across that bulb.

And then there is the CVR-what of that-->and please do not go on about how those wire wound resistors are no good because they have inductance,as no inductance at all can be seen on the scope from that CVR at these low frequencies. How is it that in the last video,the voltage across the CVR remained the same,indicating that the current flowing through the system was the same,and yet my very reliable amp meter says the current increased by 70mA when the cap was conected.

In this thread,only those that can ! show ! what they say to be true will be taken notice of. So your first task is to show Quote: Incandescent bulbs tend to regulate the current flowing thru them.  As more voltage is applied to the bulb and it attempts to draw more current, the temperature of the filament increases, which increases the filaments resistance, which reduces the current flowing thru it.
So i would like you to show us how you can increase the voltage across an incandescent bulb,while maintaining or decreasing the current flowing through it. Show us how you can dissipate more power from an incandescent bulb with less current flowing through it,and dissipate less power with more current flowing through it-->as i have shown.

I have shown the effect in the form of experiment's,and presented those experiments and results by way of video. In this thread,those that choose to argue the point will do so with actual experiments-->(! not text book physics !),and will present there experiment right here on this thread. No credibility will be given here to words without experimental  data to back up there claims.
Words are no longer good enough.

P.S
I would like to add this quote from ION
Quote:  Even the lowly incandescent bulb can be viewed as a measuring device.


Brad

[EMJunkie]

I am very serious PW,and i think you missed the boat here some where.
Did you watch the first two video's ? ,do you know what this thread is all about.

Please post a short video here showing us how you can raise the voltage across an incandescent bulb without the current also rising. Yes,the resistances rises as the element rises in temperature,but in order to gain a temperature rise,the current flowing through that bulb must increase,and as the temperature rises,so will the visible light output.


This is telling me that you have not watched the first video,where there was no solar cell being used,and the rise and fall of visible light was very apparent. Once again,the only way to increase the visible light output of an incandescent bulb is to increase the current flowing through it-->which will increase the voltage across that bulb.

And then there is the CVR-what of that-->and please do not go on about how those wire wound resistors are no good because they have inductance,as no inductance at all can be seen on the scope from that CVR at these low frequencies. How is it that in the last video,the voltage across the CVR remained the same,indicating that the current flowing through the system was the same,and yet my very reliable amp meter says the current increased by 70mA when the cap was conected.

In this thread,only those that can ! show ! what they say to be true will be taken notice of. So your first task is to show Quote: Incandescent bulbs tend to regulate the current flowing thru them.  As more voltage is applied to the bulb and it attempts to draw more current, the temperature of the filament increases, which increases the filaments resistance, which reduces the current flowing thru it.
So i would like you to show us how you can increase the voltage across an incandescent bulb,while maintaining or decreasing the current flowing through it. Show us how you can dissipate more power from an incandescent bulb with less current flowing through it,and dissipate less power with more current flowing through it-->as i have shown.

I have shown the effect in the form of experiment's,and presented those experiments and results by way of video. In this thread,those that choose to argue the point will do so with actual experiments-->(! not text book physics !),and will present there experiment right here on this thread. No credibility will be given here to words without experimental  data to back up there claims.
Words are no longer good enough.

P.S
I would like to add this quote from ION
Quote:  Even the lowly incandescent bulb can be viewed as a measuring device.


Brad

@Tinman, you do great work, always!!!

in an Incandescent Bulb, Resistance changes with heat - See: Nonlinear Conduction

Any Resistor that changes in Temperature will suffer changes in resistance.

An Incandescent Bulb is not Linear...

   Chris Sykes
       hyiq.org