inductance in a capacitor???
where's the coil? capacitance reactance or impeadance acts similar to inductance, but in oposite phase. Not as important for a filter cap as the manufacturer and quality of the capacitor. Anyway, paralelling caps or not, the ripple is a fuction of rectifier frequency or refresh rate, total capacitor value and output current, as long as the RMS output current is less than or equal to the transformer current rating.
Timfishy could use 2 or 3 4700uF caps in paralell which would be 9400uF or 14,100uF just as well. Physical construction and good solder joints are important as high current spikes and peaks will have a voltage drop across a poor solder connection, creating heat and making the connection worse over time.
where's the coil? capacitance reactance or impeadance acts similar to inductance, but in oposite phase. Not as important for a filter cap as the manufacturer and quality of the capacitor. Anyway, paralelling caps or not, the ripple is a fuction of rectifier frequency or refresh rate, total capacitor value and output current, as long as the RMS output current is less than or equal to the transformer current rating. Timfishy could use 2 or 3 4700uF caps in paralell which would be 9400uF or 14,100uF just as well. Physical construction and good solder joints are important as high current spikes and peaks will have a voltage drop across a poor solder connection, creating heat and making the connection worse over time.
Hi cunningham,
The coil is in the way the capacitor is made. The foil is wound around in a cylinder to increase plate area. Any guesses as to why a filter cap is cylindrical in shape? Right.
The audio caps are supposed to have reduced inductance by connecting the plates continuously at each end on a disc, or circular plate. This inductance can be measured, and I do, with an HP 4263A LCR meter. Yes, I'm spoiled.
The other point is that a piece of wire has inductance. The higher the current spike, the more noticable it is. A short duration spike will show this effect easily. Like the short duration charging current into a big capacitor. This is easily observed on an oscilloscope on the terminals of a large cap, with even a 1A draw.
Yes, Timfishy could use 2 or 3 4700uF caps in parallel just as well. This is the course I was suggesting, rather than purchase a big and problematic capacitor.
-Chris
The coil is in the way the capacitor is made. The foil is wound around in a cylinder to increase plate area. Any guesses as to why a filter cap is cylindrical in shape? Right.
The audio caps are supposed to have reduced inductance by connecting the plates continuously at each end on a disc, or circular plate. This inductance can be measured, and I do, with an HP 4263A LCR meter. Yes, I'm spoiled.
The other point is that a piece of wire has inductance. The higher the current spike, the more noticable it is. A short duration spike will show this effect easily. Like the short duration charging current into a big capacitor. This is easily observed on an oscilloscope on the terminals of a large cap, with even a 1A draw.
Yes, Timfishy could use 2 or 3 4700uF caps in parallel just as well. This is the course I was suggesting, rather than purchase a big and problematic capacitor.
-Chris
that is what i'll probably do, im pretty broke at the moment so i will have to leave it.
With the set-up at the moment i dont have any hum from the speakers and the music sounds great. The only thing i can imagine that can happenis that if im drawing enough power the caps wont be able to keep the power rails flat and that ripple will start to kick in. But even at reasonably high loads i cant hear any 100hz
Tim
With the set-up at the moment i dont have any hum from the speakers and the music sounds great. The only thing i can imagine that can happenis that if im drawing enough power the caps wont be able to keep the power rails flat and that ripple will start to kick in. But even at reasonably high loads i cant hear any 100hz
Tim
If you are looking for capacitors, you could try www.illcap.com.
I found the people at Illinois Capacitor very helful and friendly when requesting samples of some capacitors for a school project.
I found the people at Illinois Capacitor very helful and friendly when requesting samples of some capacitors for a school project.
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