Measure Voltage with a Voltmeter

A voltmeter is a device that measures voltage, the electrical pressure in a circuit. In this activity, you will learn how to measure the voltage across an element in a circuit using a micro:bit-based voltmeter.   Knowing how to take voltage measurements is essential when working on electrical equipment.  Examples include:

• Checking battery voltage in a robot before a contest
• Repairing just about anything electrical, including appliances, conveyor belts and other factory equipment, heating and air systems, alarm systems, and more…
• Testing of engineering design prototypes

Parts & Circuit

Let’s re-use the setup from First Breadboard Circuit — Build the LED Circuit, shown again below. In addition to the basic setup and previous LED circuit, you will need an additional resistor.

(1) LED, green
(1) Wire, black
(1) Resistor, 220 ohm (red-red-brown)
(1) Resistor, 1000 ohm (brown-black-red)

• Use the animation with the instructions below it to build your LED circuit with the 220 ohm resistor.
• Optionally, view the led-circuit-dc-green.mp4 clip to play and pause it between steps.