The ua723/lm723 Voltage regulator IC inner circuit using discreet elements. As u can see the output is astonishingly stable at 63W with a ripple of less than 10mV and this goes up to 90W with external pass transistor. As for the ic itself it provides 150mA at 1-37V and there are dozens of circuits involving this particular ic and they include adjustable current limiting capabilities floating regulator switching regulator and many others. Using this chip only and a few external parts one might make a professional power supply unit for under 10$. The ic also provides short circuit protection and many other cool features like overload protection etc if the correct outer circuit is used. I find this little chip very handy because it does not require any particular skills to use end exploit. the only downside is that if any external transistor should fail just dont bother looking for the problem and go buy a new ua723 and a new transistor. Another downside is that it has a gazilion pins and they can be easily mistaken and again the ic fails. So my advice if you are going to use this ic get a few of them (i blew 2 already)be careful with the pin numbers or just use the simpler still quite good for low power applications LM317 :)