I'm embarrassed to ask, but I've not turned up a direct answer with my search attempts.
I'm looking at a Dumbleator schematic and working up a layout...for the film caps, the layout lists voltages on them while the schematic does not. Is there a down side to using a 600V PS cap when 400V is called out on the layout?
Newbie question - Capacitor Voltage Rating
Moderators: pompeiisneaks, Colossal
Newbie question - Capacitor Voltage Rating
Sean Chaney
Re: Newbie question - Capacitor Voltage Rating
yeah, it's presenting a packaging challenge. I'm redoing the layout.
Sean Chaney
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Stevem
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Re: Newbie question - Capacitor Voltage Rating
Yes, there is a downside to having a very voltage over rated filter in a amps power supply, that being that when the voltage is applied the cap will not form up to its stated uf value!
In other words if you are using let's say a 30 uf cap rated for 600 volts like you asked about it will only form up to something less then 30 uf with only 450 volts applied.
You should increase the uf value of the filters you are using if you want the good benefits of having a higher safety range in your filters and a 50 volt safety range is plenty.
In other words if you are using let's say a 30 uf cap rated for 600 volts like you asked about it will only form up to something less then 30 uf with only 450 volts applied.
You should increase the uf value of the filters you are using if you want the good benefits of having a higher safety range in your filters and a 50 volt safety range is plenty.
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Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Newbie question - Capacitor Voltage Rating
He is using film caps, not electrolytics.Stevem wrote: ↑Sat Aug 29, 2020 9:33 am Yes, there is a downside to having a very voltage over rated filter in a amps power supply, that being that when the voltage is applied the cap will not form up to its stated uf value!
In other words if you are using let's say a 30 uf cap rated for 600 volts like you asked about it will only form up to something less then 30 uf with only 450 volts applied.
You should increase the uf value of the filters you are using if you want the good benefits of having a higher safety range in your filters and a 50 volt safety range is plenty.
Re: Newbie question - Capacitor Voltage Rating
Yep, he's talking about film caps.
@Stevem:
Your concept of cap forming up and down is backward. Electro caps get higher voltage by growing thicker oxide. This lowers the capacitance. So an electro that is run at a lower voltage eventually forms down in voltage and up in capacitance as the oxide gets thinner.They do change, but the as the voltage goes up, the capacitance goes down.
@Stevem:
Your concept of cap forming up and down is backward. Electro caps get higher voltage by growing thicker oxide. This lowers the capacitance. So an electro that is run at a lower voltage eventually forms down in voltage and up in capacitance as the oxide gets thinner.They do change, but the as the voltage goes up, the capacitance goes down.
"It's not what we don't know that gets us in trouble. It's what we know for sure that just ain't so"
Mark Twain
Mark Twain
Re: Newbie question - Capacitor Voltage Rating
Thanks all! I bit the bullet and ordered new caps of a few different styles to find an efficient way of doing this layout. It was going to be a lot of work to package the 0.22uF
Sean Chaney