Capacitor voltage rating

[skyymanz]

Hi all,

anyone know wat will be a save range to chose for a capacitor voltage rating? i want to filter a ripple signal from a 48V output rectifier. the capacitor i use should have what voltage rating? thanks!

cheers!
Skyy

 

[instruite]

I assume by 48V you mean RMS value (i.e. constant DC value)
so the Peak voltage of your signal will be 48*(2^0.5) = 68V
and we normally keep safety margin of 1.5
So you requirment will be 68*1.5 = 102V

So I will recommend you to use a capacitor with atleast 100V rating

The following link might be useful for you
https://www.electronics-tutorials.com/basics/power-supply.htm

 

[shamikrudra]

Hi all,

anyone know wat will be a save range to chose for a capacitor voltage rating? i want to filter a ripple signal from a 48V output rectifier. the capacitor i use should have what voltage rating? thanks!

cheers!
Skyy

u can use 63 V or for more 100V for safty
but consider the space 100V will be bigger in size

 

[skyymanz]

Hi instruite

Thanks for the reply!

 

[mstechca]

personally, I double the applications requirement just incase AC voltage is used. so 48 * 2 = 96. capacitors with higher numbers are much better.

 

[Laplink]

Greetings,
A capacitor with a working voltage of at least 48 volts will work. A 50Volt capacitor will work but as with anything pushed to it's maximum limit, it's life will be limited. A manufacturer may use a 63 Volt capacitor to save their $0.02c worth.
I am with Mstechca, I like to double the rating, so 100 Volts it is!
Also if it will be mounted near anything warm like a heatsink, large resistor or such, use a high temperature capacitor (105 degrees celcius) for longer life. I guess you are rectifing 120 Hz and not high frequency so ESR is of no consideration?

 

[dramrattan]

Capacitor near large resistor

To Laplink:

From what value would you consider a large resistor? 100K?

 

[superbrew]

From what value would you consider a large resistor? 100K?

Large as in power disspipation, therefore potentially generating alot of heat.