Practice moving the circuit components until you are confident you can construct a circuit. You can use the wires as many times as you like, and it is helpful to make the wires longer rather than shorter by using several spaces for a wire rather than just one space. The ammeter measures electric current and must be placed in series at the point where current is to be measured. In this simulation, however, you need only hover the ammeter over any wire in the circuit to read the current at that point. Practice manipulating the ammeter until you are confident you can measure a current. A voltmeter measures electric potential difference and must be connected parallel to the energy source or load across which electric potential difference is being measured. The voltmeter will give you a negative reading (such as -3 V) to indicate a drop in electrical potential. When measuring a load, the red wire (voltmeter lead) should be closer to the battery's positive terminal than the black lead, so as to provide you with a "drop" (negative volts). Practice manipulating the voltmeter until you are confident you can measure an electrical potential difference