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Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Physics of mechanics 204A, the centripital motion of a spinnning obect, with analyzing the energy as given in a graph of the derivative and a whole bunch of other stuff i cant figure out.
Registered Member #3943
Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552
Patrick wrote ...
Physics of mechanics 204A, the centripital motion of a spinnning obect, with analyzing the energy as given in a graph of the derivative and a whole bunch of other stuff i cant figure out.
Sounds fun ( :
A question regarding the TVS, what is the difference between uni and bi directional ones? and will it matter which I use?
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
maybe bidirectional is better for you, so you dont need to worry about the cathode band posistion.
A unidirectional TVS has a low forward drop in normal use (like a normal diode) and then blocks reverse voltage until the clamping voltage is reached, then it conducts in the opposite direction too.
a Bidirectional TVS refuses to conduct in either direct, until the clamp voltage is reached, then it will conduct from either direction. so it behaves like two zeners in series pointed in opposite directions.
Registered Member #3943
Joined: Sun Jun 12 2011, 05:24PM
Location: The Shire, UK
Posts: 552
Patrick wrote ...
maybe bidirectional is better for you, so you dont need to worry about the cathode band posistion.
A unidirectional TVS has a low forward drop in normal use (like a normal diode) and then blocks reverse voltage until the clamping voltage is reached, then it conducts in the opposite direction too.
a Bidirectional TVS refuses to conduct in either direct, until the clamp voltage is reached, then it will conduct from either direction. so it behaves like two zeners in series pointed in opposite directions.
Thanks that makes sense and clears things up ( :
Lol I know which end of a diode is the cathode XD I know basic electronics but don't really know any advanced stuff or working out solutions to problems with circuits yet.
Registered Member #4127
Joined: Fri Oct 07 2011, 05:40PM
Location:
Posts: 22
Patrick wrote ...
Alex1M6 wrote ...
Ok so is this what happens?
Yes, my brain is hurting though, dam it.
EDit: you can increase the turns on your primary if you want lower curretn than 10 amps, mine uses 30T, and draws 4 amps @ 85 volts (with 65 volts across the 30T primary. 4 amps through it) And my freq is about 15kHz at a 30% Duty Cycle.
This (increasing the turns on the primary) would reduce the final voltage, doesn't it? Or do flybacks work differently in that the resonance influences the final voltage more than the ratio of primary to secondary?
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
mzincali wrote ...
This (increasing the turns on the primary) would reduce the final voltage, doesn't it? Or do flybacks work differently in that the resonance influences the final voltage more than the ratio of primary to secondary?
The flyback or LOPT is a special device, (technically not a transformer but a coupled inductor), there is an optimized number of turns for each flyback, unfortunately you kinda have to guess up and down till you get it right. the Flyback doesnt have a "precise" turns ratio, theres the initial EMF step up cross the primary, 300 or more V then the secondary turns step that up, then the collaspe of the secondary inductance and air gap boost it a bit more, thus the final high voltage. Theres alot of stray factors when wire is coiled up N thousand times, that ends up making a exact turns ratio not really possible.
I try to use the orignal primary when ever possible. But you generally need 50-150 volts to make the internal primary usefull.
Registered Member #4127
Joined: Fri Oct 07 2011, 05:40PM
Location:
Posts: 22
What's the best way to boost the initial 12volts up to 50-100 volts, before feeding to the original primary?
I tried using a ferrite ring with 10 windings on one side and 40 on the other, but got nothing of note. I was hoping to connect that straight up to my flyback, since I don't have a lot of high voltage components lying around. (I do have a couple of old computer monitors I can rob - I already took their flybacks).
Would a ferrite rod be better than a ring? Seems like there is a lot to learn about inductors and transformers, like how they don't burn out the transistor when they have so little resistance and seem to just provide a short circuit from ground to Vcc through the transistor.
Also, when winding my own primaries, does it matter what gauge of wire I use?
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555 flyback transformer MOSFET gets hot.
