Mendelt

Correct. Another thing you should take into account is that your capacitors get 100 peaks (120 in the US) every second but the voltage in between peaks drops to 0V. The trick is making sure you dont deplete them too much in between peaks. When your supply just supplies 100mA you can use small capacitors because you're not discharging them very fast. But when you're building a bigger supply you need bigger capacitors so they can hold more charge.

Yup. The regulators need about 2 volts more than their output to regulate correctly. So If you put in a 7809 you need a capacitor big enough to store enough electrons to keep the input of the regulator above 11V.

The 0,7V is the rectifier dropping the voltage :) And the 41% isn't really the rectifier upping the voltage but that's due to the 12V at the input of the rectifier being 12V AC. That means that the average voltage is 12V but the peak voltage can get much higher. For a sine wave you can just multiply the average with the square root of 2 to get the peak voltage. The capacitors after the rectifiers will store the voltage you put in them. They will lift the voltage to the peak voltage they receive. That's where the 41% comes from. But I see everyone has fallen asleep so I'll stop the useless technical explanations ::)

Hey, I see you've been working on this behind my back ;D You can do this with one less rectifier, just connect the two center leads of the trafo together to earth and connect the positive side of the rectifier to the positive line and the negative side to the negative line. It should look a bit like this http://1176neve.tripod.com/id26.html

Was the PSU connected to anything when you measured the 8 and 7.5 volts? You need to draw some current from most regulators before they start regulating well. According to the 7809 datasheet from Fairchild the dropout voltage for these regulators is 2V. So with a normal load attached and an input voltage of 11V everything should work. You don't need the bleeder resistors paralel with the capacitors. The regulators will bleed the capacitors when you turn off the PSU. You could use inrush-current limiting resistors to limit current through the diode bridge. But you have to use much lower value resistors. and you have to put them in series before the diode bridge.