One of the most needed instruments in electronics lab is adjustable power supply, allowing you to feed each circuit is tested or constructed for the required voltage and current. 
The adjustable power supply circuit shown here is just a linear power supply, a bridge rectifier and filter capacitor that it attach series voltage regulator. Furthermore, here was provided by a pair of fixed instruments that allow us to know at any time the voltage given in the output and load current used.
For this circuit to work properly the load must be at least 5 mA. Integrator has TO-3 package, known as the 2N3055 or BU208 cite a few examples that will be familiar to all. Below is explained how to identify each terminal of the IC LM350K :
Cooling for this component is the key to success for proper regulation and stabilization of the output voltage. This component has cut over temperature, so if is poorly dissipated it will be off. An alternative is to mount it very reliable in a heatsink of AMD Athlon microprocessors, which have the appropriate size and fan. If you are not electrically isolate the integrated heatsink shall suspend the whole cabinet to avoid short circuits.
