This is a high quality power supply with a continuously variable stabilised output adjustable at any value between 0 and 30VDC. The circuit also incorporates an electronic output current limiter that effectively controls the output current from a few mill
http://www.electronics-lab.com/projects/power/003/index.html
This circuit provides 0-30 volts, at 1 amp, maximum, using a discrete transistor regulator with op-amp feedback to control the output voltage. This power supply has constant current mode suitable for charging batteries.
http://members.tripod.com/michaelgellis/power2.html
This is a simple regulated power supply that can give adjustable voltage from 3 volts to 18 volts. The current capacity is 10 amperes. This circuit is overcurrent protected. This circuit can be modified for higher current ratings if needed.
http://www.anatekcorp.com/ttg/tiptrick.htm#10 amp Power Supply
This is a simple, but low-ripple powersupply, and an excellent project if you're starting out in electronics. It will suit your needs for most of your bench testing and prototype applications. The output is adjustable from 1.2 volts to about 30 volts. Max
http://www.uoguelph.ca/~antoon/circ/vps.htm
regulated power supply can be adjusted from 3 to 25 volts and is current limited
http://ourworld.compuserve.com/homepages/Bill_Bowden/page4.htm#ps3.gif
well filtered variable 1.2-30 volts at 5 amps using LM338K
http://www.aaroncake.net/circuits/supply.htm
uses pair of 3N3055 transistors to give out currents up to 15A
http://ourworld.compuserve.com/homepages/Bill_Bowden/page12.htm
This is a simple circuit which can provide an adjustable voltage source of 0 to 330 Volt. The supply is short-ciruit proof: the current is limited to about 100mA.
http://www.geocities.com/tjacodesign/300vsup/300vsup.html