The Extech Digital DC Power Supply is an excellent choice for the science classroom. It has three outputs: adjustable 0-30 V at 0-3 A, fixed 5 V, and fixed 12 V. It provides constant current or constant voltage modes and has overload and short circuit protection. Binding post terminals are provided for the variable supply. Easy snap terminals are provided for the 5 V and 12 V outputs. The front panel contains digital voltage and current meters for the variable output, so you won't need additional metering in a typical experiment. This power supply will work perfectly with the activities in our physics lab manuals that require DC power.