Hi, I am using the LM7805 and the LD33V voltage regulators in my project. What capacitors should I use for the regulators? I have 10uf and 4.3uf capacitors. Can I use these capacitors? It would be a great help if you could also tell me how you calculated which capacitors to use. Thanks in advance and thank you for your time 
You look in the data sheet of the manafacature of the specific device you are using. It will tell you the minimum value there. This is something that you do not know enough to calculate.
Thanks
suersaiyangod:
Hi, I am using the LM7805 and the LD33V voltage regulators in my project. What capacitors should I use for the regulators? I have 10uf and 4.3uf capacitors. Can I use these capacitors? It would be a great help if you could also tell me how you calculated which capacitors to use. Thanks in advance and thank you for your time
Insufficient information. Are these for input to the regulator, or on the output side? Are you regulating a battery voltage, or regulating from a rectified AC source? If AC, are you using a 1/2 wave or a full wave rectifier? If AC, what is the AC frequency? If AC, how much ripple can your project handle?
Really, you should not even have to ask a question like this. Do you have an oscilloscope to see the output of the regulator? If so, try each capacitor and see if you like the trace. If ripple is too great, tack in a second capacitor, or a third, and see if the ripple on the trace is acceptable.
Paul
Sorry that I didn't give the details. I'm using a 9v battery. I need the capacitor values for both output and input of the regulators.
10uF on input and 4.3uF on output are fine. Make sure to use 0.1uF on Vcc pin of every IC you are powering.
Is it ok to not use the 0.1uf capacitors? I'm using an Arduino pro mini. Can I also swap the capacitors that you mentioned (4.3uf on input and 10uf on output OR 4.3uf on both input and output)? Will all these work for both the regulators or only one of them?
Is it ok to not use the 0.1uf capacitors?
No. It handles the high frequencies. See:- http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html
But see the data sheets, different manufacturers have different requirements for the same part. I once had several thousand pounds of production scrapped because some one in purchasing thought they could replace one manufacturers LM7805 with the same part from another manufacturer. They required different capacitor values and the replacement caused the supply to oscillate which caused an audio sensitivity test way down the line to fail.
Grumpy_Mike
Seems a lot of scrappage - couldn't you get the LM7805's or the caps changed? Or was the rework too expensive, or the leadtime on components unacceptable?
Loads of things go wrong on a line - not all are irretrievable.
Allan
Can I use 22pf ceramic capacitors instead of 0.1uf??
suersaiyangod:
Is it ok to not use the 0.1uf capacitors? I'm using an Arduino pro mini. Can I also swap the capacitors that you mentioned (4.3uf on input and 10uf on output OR 4.3uf on both input and output)? Will all these work for both the regulators or only one of them?
Arduino pro mini has all the caps and a regulator. Or not?
4.3uf is not a standard value. 4.7uf would be the nearest easily obtainable one. 22pf is too small for decoupling.
suersaiyangod:
Can I use 22pf ceramic capacitors instead of 0.1uf??
Did you read that link I posted?
You think a capacitor of value five magnitudes smaller will do. No it **** won't.
I did read the link and I only understand a little. Sorry but I'm new. Can I use 4.3uf or 10uf instead of 0.1uf?
It is similar to cooking.
The recipe for the cake says: 5 eggs.
It may work with 4 eggs, it may work with 6 eggs.
But if you say "i want to use 500 eggs" or "i have only 1 egg" it may come out a completely different cake.
Be aware of the unit prefix:
µ 0.000001 micro
n 0.000000001 nano
p 0.000000000001 pico
Can I use 4.3uf or 10uf instead of 0.1uf?
0.0000001 this should be used (5 eggs)
0.0000043 this 43 times more (215 eggs)
0.0000100 this is 100 times more (500 eggs)
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Can I use 4.3uf or 10uf instead of 0.1uf?
FFS no.
The 0.1uF needs to be a ceramic.
I did read the link and I only understand a little.
In that case do not argue with advice.
suersaiyangod:
I did read the link and I only understand a little. Sorry but I'm new. Can I use 4.3uf or 10uf instead of 0.1uf?
If you don't understand it, then don't deviate from what is recommended. The people who designed it DO understand, and determined those values to produce the expected output. What you are asking is for someone to justify your future failure.
I get it now.Thanks