Voltage Regulator

Hi, hoping i'm in the correct category for this one.
I'm still learning the basics so have basic questions.

I've bought some L7805CV 5V voltage regulators and the data sheet if I have read it correctly says that I need a .33uF capacitor at the source power and a .1uF capacitor on out power obviously both to ground, which I can understand.

What I am after is how does it affect things if you using different ratings?

I would guess that if you used lower ratings then you risk an uneven circuit, but if you increase them does it just mean a delay in the initial power?

For example what happens if you stick in a 4.7uF and a 1uF keeping the larger at the source?

What I am after is how does it affect things if you using different ratings?

You mean values not ratings. Ratings are things like maximum voltage, and ripple current.

Basically making the capacitors bigger do not make much difference, but making them smaller can lead to instability and oscillations of the regulator.

Thanks for the reply,

Yes I would have thought that they could cause issues if too small, is it just the case that they take longer to build their power supply up before the circuit is fully functional then?

No. The time it takes a capicitor to charge up is determined by the capacitor value and the resistance of the charging source. The time constant of a circuit is found by multiplying the resistance in ohms by the capacitance in Farads. At three times this value the capacitor can be considerd fully charged. This is a very small fraction of a second even with the biggest capacitors.

If the capacitance is too big and I am talking of thousands of micro Farads, then some switch mode regulators might not be able to start, but that is not what you are asking about.

The reasion for wanting as small a capacitor as you can get away with are simply that smaller capacitors are physically smaller and on the whole cost less.