Hi, I have two questions about power supplies. I am just curious of what is practical and possible. i) I have been using a 30V wall wart regulated to 18V for a radio telescope project (using LM317). The load does not really need a set 18V, and could actually swing between 13V and 18V. The current on the other hand should stay close to 200 mA. Is there a way to limit current to this value while allowing voltage to swing through or be within that range? ii) In the same project another part of the circuit requires a regulated 5V supply. I was curious what might be the best way to merge the two so that I only have one single plug. The way I understand things, simply using the 30V for both regulators would cause a huge power dissipation on the 5V regulator especially.