Resonance Circuits and Resonance Systems

[Low-Q]

playing around with capacitors and non-polarized and polarized (electrolytic) is pretty clear, but how about frequency? Can I use just any cap with 50kHz AC or square wave? What if the voltage is is in the range on megahertz?

What if the pulses are square wave from 0 to 5V of 50 kHz? Is that considered pulsed DC and AC only when it goes negative too?

Some of these signal / power sources are pretty unclear what they mean when they say AC or DC. They say AC if it is something else than a constant 5V

DC is DC as long the signal is on either the positive or negative side all the time - regardless of pulses or variable signal. As soon as the signal cross the zero line in to opposite polarity, current starts to flow the other direction, you got AC.


You need AC, but that can be achieved with pulsed DC as long as you connect a capacitor in series first. This high pass filter will lett the pulses through, and let the DC component rest over the capacitor.


Vidar

[Belfior]

DC is DC as long the signal is on either the positive or negative side all the time - regardless of pulses or variable signal. As soon as the signal cross the zero line in to opposite polarity, current starts to flow the other direction, you got AC.


You need AC, but that can be achieved with pulsed DC as long as you connect a capacitor in series first. This high pass filter will lett the pulses through, and let the DC component rest over the capacitor.


Vidar

Thx Vidar,

so non-polarized caps I can connect to DC or AC and the frequency is going to be a problem only if the MHz is so high it shorts the cap. Meaning the cap can't change polarity as fast as the current.

Electrolytic also, if I make sure the polarity is right?

I got microwave oven caps rated 2100V 50Hz AC 0,8uF and they seem to take charge from secondary coil + full wave rectifier just fine. Cap shows 41V

[Low-Q]

You're talking MHz. A cap at 0.8uF is considered as a full short circuit at that frequency range unless you want it to be a capacitor to block DC and conduct AC.

Z=1/(2×pi×f×C)
Z=1/(2×pi×1 000 000Hz×0.0000008F)=0.2 Ohm

Vidar

Thx Vidar,

so non-polarized caps I can connect to DC or AC and the frequency is going to be a problem only if the MHz is so high it shorts the cap. Meaning the cap can't change polarity as fast as the current.

Electrolytic also, if I make sure the polarity is right?

I got microwave oven caps rated 2100V 50Hz AC 0,8uF and they seem to take charge from secondary coil + full wave rectifier just fine. Cap shows 41V

[Magluvin]

Mag,
I can't fully understand how you can get overunity out of a resonance system.
It's easier to understand the resonance concept by using a low loss spring, and a mass attached to it. The spring is the capacitor and the mass is the inductor.


If you try to extract output from the mechanical system, you also remove the reason why it resonate.
Say you put cotton whool inside the spring. The cotton is the load you want to put energy in to.
Now the resonance system has a low Q, and is no longer willing to sustain oscillation without energy supply.


My nick, btw, reflects this low Q as a speaker system with controlled audioable output. You cant get controll without effort.


Vidar

Not very low loss but it is stainless strap. I made a different magnet config but hadnt gotten back to that yet since. The new magnet sets are sam poles facein and a spacer. So the field between the mags is perpendicular to the axis of the pole face. The flux comes out radially around the spacer so the flux is at right angles to the windings. Should be better performance with that...

https://www.youtube.com/watch?v=cVEmF_J_f3s&t=198s

https://www.youtube.com/watch?v=5Fmmg9UXnw4

Stiffer stainless... Less air resistance

https://www.youtube.com/watch?v=2OTyErrA9N8

Then magnetic spring... Its different as the freq is dependent on level of input. So freq increases as you drive it harder. It seems to be a non linear spring.

https://www.youtube.com/watch?v=rDinA8Zm4LQ

Mags

[Low-Q]

Springs are not linear. Their tension increase with amplitude.
If you pluck a gitar string very hard, you can hear that the pitch start high, then it pitch down as the amplitude decrease.

Not very low loss but it is stainless strap. I made a different magnet config but hadnt gotten back to that yet since. The new magnet sets are sam poles facein and a spacer. So the field between the mags is perpendicular to the axis of the pole face. The flux comes out radially around the spacer so the flux is at right angles to the windings. Should be better performance with that...

https://www.youtube.com/watch?v=cVEmF_J_f3s&t=198s

https://www.youtube.com/watch?v=5Fmmg9UXnw4

Stiffer stainless... Less air resistance

https://www.youtube.com/watch?v=2OTyErrA9N8

Then magnetic spring... Its different as the freq is dependent on level of input. So freq increases as you drive it harder. It seems to be a non linear spring.

https://www.youtube.com/watch?v=rDinA8Zm4LQ

Mags