The DC power supply is used to generate either a constant voltage (CV) or a constant current (CC). That is, it may be used as either a DC voltage source or a DC current source. You will be using it primarily as a voltage source. Recall that DC is an acronym for direct current. DC means constant with respect to time. The HP3611 DC power supply has two range settings. The first range setting allows the power supply to produce between 0 and 20 volts (V) and has a maximum current capacity of 1.5 amps (A). The second range setting allows it to generate between 0 and 35 V with a maximum current capacity of 0.85 A. The voltage produced by the power supply is controlled by the knob labeled voltage. The current is limited by adjusting the knob labeled current. As long as the circuit does not atttempt to draw more current than the value set by the current knob, the voltage will remain constant. This is often a difficult concept for students to grasp. Current limiting allows the power supply to be set such that it will not generate more current than desired. This can be useful as a safety feature, preventing electrocution due to accidental contact with terminals. In addition, current limiting can prevent damage to equipment and parts which may be unable to handle excessive currents. More details about current limiting will be presented in the experimental procedure.