Measuring the current requirement of a relay and LED

We will also measure the current draw of an LED and the relay we will use in this chapter when we reach the section titled Using a relay as a switch. You can measure the current draw using steps 1 to 4 from the preceding section. The setup to perform this measurement for an LED and resistor pair is illustrated here:

Figure 7.4 – Measuring current through a resistor/LED circuit

This is the basic process we follow:

1. We attach an LED and a 1kΩ resistor (or a relay) in place of the motor shown in Figure 7.3.
2. Set your multimeter to milliamps mode.
3. Apply power to the circuit.
4. Measure the amperage on your multimeter.

Once you have performed (and jotted down) the measurement you receive, remove the LED and resistor from the breadboard and wire in your relay and perform the same measurement.

The following diagram shows an SRD-05VDC-SL-C relay and which terminals on your relay you need to connect. Please note that you...