Current

Current

Current is also a key characteristic of an electric circuit. Current describes the amount of electricity that flows through a circuit. Back to our stream analogy, current describes the amount of water that is flowing in a stream. 

Current is measured through the multimeter. The multimeter has a low-current setting and a higher-current setting.  This is why it is important to get a rough idea of the current before hooking up the multimeter. A good piece of advice is: When in doubt, start with the 10 A connection!

Below is the single LED circuit you built in Lesson 1. As you built the circuit, the energy flowed from the hot terminal, through the LED, and returned to the Load Center through the neutral terminal.

To measure the current, we need to ‘break’ the circuit and make the multimeter part of the circuit. Note: since we do not know the initial current value, the multimeter is connected to the circuit through the 10 A probe on the left.

Now, the energy is going from the Load Center to the LED and then into the red probe connected to the 10A port of the multimeter, through the multimeter, to the COM probe of the multimeter, and finally back to the neutral of the Load Center.

The current, as it shows, says 0.019 A or 0.019 amps. The port on the left can take up to 10A of power, so this is more than safe. But, when turning to the mA and μA settings, the multimeter reads zero. The port on the right is more sensitive and can handle a current of 600mA or 0.6A. Since the current is less than 0.6A, we can connect the circuit using the right probe port.

Now, with the probe connected to the right-side port, we can see that the current in this circuit is 19.15 mA or 0.01915 A