Unfortunately, you probably don’t have a multimeter and components to build a circuit wherever you’re reading the website. So, we’ll have to treat this as a theoretical practical[i].              

Voltage and current can be altered to change the properties of a circuit. So it’s important that we’re able to measure them. For now, we’ll not go into what these actually are because their definitions are very confusing.  

The important thing to remember is that voltage is always measured in parallel, and current is always measured in series. The component used to measure current is an ammeter (a circle with an a) and the component used to measure voltage is a voltmeter (a circle with a v). 

                                                                                                                              The two circuits below show where you place the meters when measuring the two quantities.

 The most important thing to note is that the ammeter is inside the main circuit (in series) and the voltmeter is connected by wires into the circuit (in parallel).  

When the metre is connected into the circuit you just need to read off the numbers.