Would it be safe to use 4700uf instead of 3300uf capacitors in a tapedeck power supply? Ive marked the ones I want to change,C336 has a ''star'' above it that just means it has a part number.I live in a fairly remote area and it takes weeks to order anything through the post but I can get the 4700uf caps here OK. Ive spent about an hour looking for a previously answered question on this subject without success.Any help would be appreciated.

 

If it will fit physically (diameter, height, lead spacing), I don't see any problem. 35 V is a minimum for this application.

ak

 

Thats good to hear! Im being careful because the tapedeck is a vintage high end Pioneer CT-W910R that Im rebuilding.Thankyou for taking the time to help me with this AnalogKid and the quicker than quick response.lol

 

As mentioned in a recent similar thread Electrolytics have typically wide tolerance value of -0% to +100% by many manuf specs.
Max.

 

As mentioned in a recent similar thread Electrolytics have typically wide tolerance value of -0% to +100% by many manuf specs.
Max.

Wow, "-0% to +100%", could you link any one to see?

 

What's reason to make you have this thought : use 4700uf instead of 3300uf capacitors?
And what kinds of load are you always used?

 

Wow, "-0% to +100%", could you link any one to see?

Just one of a few references out there, about the lowest manuf tolerance I have seen is +50%.
http://www.electronics-tutorials.ws/capacitor/cap_3.html
Max.

 

[ I will likely catch hell for this] It seems to me, that when the given capacitor is still in production, it could / should be measured for its actual individual capacity, and then labelled accordingly...
Yeah... I know... I've heard it all before... That would " Kawst teww Muuuch "

 

[ I will likely catch hell for this] It seems to me, that when the given capacitor is still in production, it could / should be measured for its actual individual capacity, and then labelled accordingly...

Your right, that's a terrible idea. Capacitors, like resistors, have "standard" values with tolerances. Values for caps used as power supply filters are not critical and good designs take typical electrolytic tolerances (of -20% to +80%) into consideration.

The tolerance figure I used is from what I've seen marked on components and/or documented in datasheets. For the questioning types, here are two online references that you can choose to believe (or not): electronics-tutorials.ws and radio-electronics.com

 

Wow, "-0% to +100%", could you link any one to see?

Out of curiosity, I searched; P tolerance is -0% to +100%:
EIA cap tolerance codes.

 

[ I will likely catch hell for this] It seems to me, that when the given capacitor is still in production, it could / should be measured for its actual individual capacity, and then labelled accordingly...
Yeah... I know... I've heard it all before... That would " Kawst teww Muuuch "

What I can accept is quite normal that is from -20%~+20%, too much tolerance will make designs become more difficult.

 

The only downside to using a larger capacitor value is that the lower ripple voltage can increase power dissipation in the pass transistor of the voltage regulator. This assumes that the cap is the same or better than the one it is replacing in all other ways.

edit: I just thought of another potential problem caused by a larger capacitance value. The surge current charging the cap will be larger. This could strain the rectifier diodes.

 

: I just thought of another potential problem caused by a larger capacitance value. The surge current charging the cap will be larger. This could strain the rectifier diodes.

It also increases the VA required value of the transformer if used at the maximum current rating.
Max.

 

It also increases the VA required value of the transformer if used at the maximum current rating.
Max.

Have you even really use the tolerance equal or over +50%?

 

Have you even really use the tolerance equal or over +50%?

Have you ever measured some of the larger capacitors for value?
In most applications I have used it is not a problem, it may even be an advantage!
Max.

 

Have you ever measured some of the larger capacitors for value?
In most applications I have used it is not a problem, it may even be an advantage!
Max.

When I measured the big capacitors as 2200 uF and 3300 uF or 4700 uF, they are all in +0~20%.