i dont know thathi,
I guess you know that for an output current of 1 amp you will drop at least 7v across the 7805, that is 7 Watts.
On lesser load currents the smoothing cap could charge to [12 * 1.4] - 2 Diode voltage drops, that is approx 15V.
Make sure your H/S can keep your 7805 within its temperature specification, if it over heats choose a larger version.i dont know that
what are the effects of these values ?!
if i do all the advises mentioned here ,is there any thing should be modified ?If you drop the transformer to 9V your regulator won't get as hot.
you mean get 9v transformer instead of 12V?
if i change the regulator from 1A to 2A ,does this affect ?
However, the 1,000uF capacitor on the input may be too small - it you can fit a larger capacitance it would be better - maybe 2,000uF 25V - may be 16V.
i will use 2200uF ^^
Thanks Erichi emb,
If the PSU was for a bench testing supply, I was going to suggest adding a 7809 [9v reg] ahead of the 7805.
This would mean you could use the existing 12V transformer, reduce the heating in the 7805 and giving a +9v and +5v supply for your projects.