Laboratory power supply is characterized by its wide adjustable voltage range and its robustness. Continuous voltage adjustment is necessary, as well as current limiter for safety and robustness. You can build suitable one using LM10 op-amp and voltage source IC as shown in the schematic diagram below:

Laboratory Power Supply circuit schematic

The output voltage is adjustable between 0-50V, with 1A maximum current. [Circuit’s schematic diagram source: National Semiconductor Application Note]