Thanks to the help of a few of the other guys I have my AC to DC rectifier working, and the rest of the power supply working.
Now while testing the power supply, my 18V AC transformer gets rectified and put into my circuit below
And I end up with 1.3-26V DC output selectable via the pot R2.
Now while running this @12V with a LED strip light, running about 600mA my heat sink got quite hot. Not hot enough to cause the thermal protection in the LM317 to cut in but hot enough to get me thinking.
Power dissipated = (Vin - Vout)*Il = (26 - 12)*0.6 = 8.4W
My heat sink is rated at 11 C/W and I pasted the LM317(TO-220) on.
Max C/W is = (MaxRunningTemp - ambientTemp) / power = (60-25)/8.4 = 4.2 C/W
Does that sound right, never done any heat sink calculations before. So I would need a heat sink rated at <4.2 C/W
I would not see my self running this over 500mA again but running this circuit at 5V would change a lot? The power dissipated would be 42W if 5V @ 500mA. What can I do to prevent needing a HUGE heatsink? and are my calculations above correct?