choosing the appropriate transformer

[crutschow]

A small Transistor Type, Audio transformer would be more Appropriate.

That would work also. But a small power transformer, such as 6V filament transformer operated in reverse, would likely be more efficient due to lower resistance windings.

 

[bazramit]

Ok whenever I can see the output of the transformer now with little distortion by means of my oscilloscope, but whenever I place a capacitor at the output the signal disappears?

 

[chemelec]

Ok whenever I can see the output of the transformer now with little distortion by means of my oscilloscope, but whenever I place a capacitor at the output the signal disappears?

If you are putting the Cap Across the Output, It will tend to Short out the Signal.
AC can flow through a Cap.

 

[bazramit]

If you are putting the Cap Across the Output, It will tend to Short out the Signal.
AC can flow through a Cap.

How should I place the cap?

 

[chemelec]

How should I place the cap?

Why do you Need a Cap?
For What Purpose?

 

[crutschow]

If you are trying to convert the energy to DC you will need a rectifier feeding the cap. A Schottky diode will have the best efficiency.

 

[bazramit]

yes I am trying to store the energy in a capacitor. I place a bridge but the problem is that the first pulse is getting stored and the rest of the pulses are not stored since the cap will have a higher voltage from the first pulse.

 

[alec_t]

A cap is like a bucket; when it's full it's full. If the first pulse charged the cap to the peak voltage of the pulse (minus the rectifier loss) then the energy of subsequent pulses can't get stored until you take some charge out of the cap.

 

[bazramit]

During the first pulse the cap is charged to about 11 volts but it can withstand 30 volts.
Since the second pulse is only about 66 volts I will not benefit from it. Do yu get it?

 

[chemelec]

During the first pulse the cap is charged to about 11 volts but it can withstand 30 volts.
Since the second pulse is only about 66 volts I will not benefit from it. Do yu get it?

It is Not just about the Voltage of these Pulses.
It is also about the Current within. (Joules of Energy)

 

[()blivion]

[rant]

A) The OP already asked this question in a different thread. Post #9 in this thread, links to that thread. Supporting thread re-posting is not really fair to those that do follow the rules.

B) I suspect the OP is in actuality an EE student, working on an assignment. As such, we should NOT do his/her work for them. And this should probably be moved to the correct section if that is in fact the case.

C) If B is however false, We would still need the OP to provide us with a more complete picture of what he/she is attempting to do, if we are to be able to help at all. Otherwise any attempt at helping is just a shot in the dark and inefficient use of expert time.


Bazramit, As Nigel Goodwin had told you in your first thread. You need to tell us THE ENTIRE STORY in detail before anyone can really help you. Otherwise this whole thing is just a pointless game of 20 questions that will get you nowhere. If you have a problem with English, there are ways to work around that. Have a friend help you. Use translation software. Try harder. IMO There is no reason you can't explain the whole story to us, unless you are doing something shady.


I don't mean to be crabby or insulting, But I was following the previous thread and was thinking the same thing back then. For all we know this guy is trying to do things completely @$$backwards when something trivial will suffice.

[/rant]

 

[chemelec]

Personally I think he is doing this for himself, just trying to get FREE ENERGY.

 

[()blivion]

trying to get FREE ENERGY.

That's almost worse...

 

[chemelec]

AHHHHHHH, But some find it is Fun to try to get the Impossible!

To Each their Own.

 

[crutschow]

yes I am trying to store the energy in a capacitor. I place a bridge but the problem is that the first pulse is getting stored and the rest of the pulses are not stored since the cap will have a higher voltage from the first pulse.

A way to store all the energy is to use the rectified pulses to drive an inductor, not a capacitor. The stored inductor energy can then be used to charge a capacitor, a sort of simple switching boost converter.

You will need a couple of switches to switch between the inductor and capacitor. You ground the output of the inductor with a switch while the inductor is storing the energy. The you open that switch and close another to connect the inductor output to the capacitor which converts the inductive current into a voltage on the capacitor.

 

[bazramit]

A way to store all the energy is to use the rectified pulses to drive an inductor, not a capacitor. The stored inductor energy can then be used to charge a capacitor, a sort of simple switching boost converter.

You will need a couple of switches to switch between the inductor and capacitor. You ground the output of the inductor with a switch while the inductor is storing the energy. The you open that switch and close another to connect the inductor output to the capacitor which converts the inductive current into a voltage on the capacitor.

OK this is fine but what should the switches be and please don't forget that this is a self powered circuit.

 

[crutschow]

OK this is fine but what should the switches be and please don't forget that this is a self powered circuit.

One switch from the inductor output to ground and one from the inductor output to the capacitor.

Self powered is a problem. Perhaps a bootstrap circuit powered by a separate diode and capacitor from the input. This would only capture the peak signal, of course, but may be enough to power the circuit initially and start the process. After that it could be powered from the normal inductor-capacitor output.

 

[bazramit]

One switch from the inductor output to ground and one from the inductor output to the capacitor.

Self powered is a problem. Perhaps a bootstrap circuit powered by a separate diode and capacitor from the input. This would only capture the peak signal, of course, but may be enough to power the circuit initially and start the process. After that it could be powered from the normal inductor-capacitor output.

a schematic would be great if this is possible

 

[ChrisP58]

Nothing energy from the second pulse will be stored, unless it's voltage is greater than the voltage already at the capacitor. So the only way to harvest energy from the second pulse is to either make it larger, or make the cap voltage from the first pulse lower than the second.

You might try using an inductor circuit like a buck converter.

-------D1----------L1-----------
            |               | 
           D2              C1
            |               |
           gnd             gnd

The cathode of two diodes is connected to the inductor, and should be schottky.

No guarantees, but this might give you some improvement.

 

[()blivion]

Nothing energy from the second pulse will be stored, unless it's voltage is greater than the voltage already at the capacitor.

If the waveform the OP has shown us is coming from about what I think it is (Some form of LC resonant circuit) then you can not, and do not need to extract anything after the first pulse. This is because the rest of the pulses are just echos of the first in an LC resonant circuit. So when you absorb all the power of the first pulse, there is no energy left to rebound and create the remaining pulses.

Of course, if the OP would only show us his entire project we could end the pointless conjecture and provide real help...