Incorrect Capacitor for voltage regulator ?

Hi all

I am wanting to use a L7808CV voltage regulator to drop my supply ( varies between 12 to 14v ) to 8 volts, to power a Mega 2560 board on the Vin pin. My thinking is that if I can supply a constant 8V to the Mega, its onboard regulator has less stress placed on it.

From research, I understand that I need 2 capacitors -- 0.33uF and 0.1uF

I have these components :

Radial Z5U ceramic cap,100nF 50V 5mm
part no : 5381449 from

KS radial Al electrolytic cap,0.33uF 50V
part no : 116975

I understand that the polarity of the capacitors is important. On the 0.33uF cap I can see the negative side printed, but on the 100nF ( is this the same as 0.1uF? ) I do not see any polarity markings.

Do I have the wrong capacitors ? If so, could you point me to the correct part numbers ?

Also, can I use the L7808 without the capacitors ? I recall that the Mega board has its own voltage regulator as it can accept up to 20V but runs on 5V.

No the parts are right. The 0.1uF is not polerised so it dosn't matter what way round it is.

Thanks a million Mike.

I really appreciate the fast reply. Am wanting to start assembly in the morning.


When I built my circuit with a voltage regulator, I use there values :

Input of the regulator : 10uF to 100uF and 100nF Voltage : above 35 V.

Output : 10uF to 47uF and 100nF Voltage : above 35 V ← in case the regulator decide to go “south”

My “standard”…