Capacitor Farad Rating and Applied Voltage HELP!

habsrock93 · 3rd January 2009, 05:56 PM

I'm a little confused. Lets say I used a .22uf (rated for 630v) capacitor in a preamp circut, but the supply voltage to the circuit is only 300v. Is the capacitor only .22uf @630v? If the capacitance changes with the applied voltage, won't this affect RIAA circuits substantially?

Defining capacitance and the farad
Q âˆ V, or Q = constant Ã— V. This constant is called the capacitance, C, of the capacitor and this is measured in farads (F). So capacitance is charge stored per volt

Thanks

Dave

Juergen Knoop · 3rd January 2009, 06:08 PM

foil-type capacitors don't change their capacitance very much with voltage.
This is more a problem with electrolytic and ceramic capacitors.
Anyway, within Q=C*U C is considered constant.
regards

habsrock93 · 3rd January 2009, 06:14 PM

So the capacitance is considered constant. Thanks for clearing that up!

Dave

3rd January 2009, 05:56 PM	#1
habsrock93 diyAudio Member Join Date: Oct 2006	Capacitor Farad Rating and Applied Voltage HELP! I'm a little confused. Lets say I used a .22uf (rated for 630v) capacitor in a preamp circut, but the supply voltage to the circuit is only 300v. Is the capacitor only .22uf @630v? If the capacitance changes with the applied voltage, won't this affect RIAA circuits substantially? Defining capacitance and the farad Q âˆ V, or Q = constant Ã— V. This constant is called the capacitance, C, of the capacitor and this is measured in farads (F). So capacitance is charge stored per volt Thanks Dave

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
PS Capacitor Voltage Rating	dsavitsk	Tubes / Valves	3	16th January 2006 02:37 AM
Oil Capacitor DC vs. AC Voltage Rating	valveitude	Tubes / Valves	2	10th June 2005 11:45 PM
Capacitor Voltage Rating	diyman	Solid State	2	21st December 2004 02:49 PM
Capacitor Voltage Rating	Super_BQ	Parts	14	22nd September 2001 03:50 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

3rd January 2009, 06:08 PM	#2
Juergen Knoop diyAudio Member Join Date: Jan 2007 Blog Entries: 3	foil-type capacitors don't change their capacitance very much with voltage. This is more a problem with electrolytic and ceramic capacitors. Anyway, within Q=C*U C is considered constant. regards

3rd January 2009, 06:14 PM	#3
habsrock93 diyAudio Member Join Date: Oct 2006	So the capacitance is considered constant. Thanks for clearing that up! Dave

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)