Series Circuits
Voltage Measurement in a Series Circuit
In this lesson, we use the Microtrainer Series and Parallel Card to measure voltage at different points in a series circuit. The goal is to help you understand how voltage divides across components and how to use a digital multimeter to verify it.
Setting Up the Multimeter
To measure voltage correctly:
Set the meter to Volts DC (solid line over dashed line).
Place the black lead in the COM port.
Place the red lead in the V/Ω port.
Turn on both the master switch and the series circuit switch on the Microtrainer.
Measuring Source Voltage
Begin by measuring the voltage between B+ and ground.
You should see around 5 volts, which is your supply voltage.
This value becomes the reference for all voltage drop measurements.
Measuring Voltage Across Each Component
Move through the circuit step by step:
Switch
You should see almost the same voltage before and after the switch.
A good switch has very little resistance, so it drops almost no voltage.
Resistor
After the 1 kΩ resistor, voltage should drop from 5 V to around 3.6 V.
This means the resistor is dropping roughly 1.4 volts.
LEDs
Each LED drops about 1.8 volts.
Two LEDs together drop 1.8 + 1.8 = 3.6 volts.
Add that to the resistor’s drop (1.4 V), and the total equals the 5-volt supply.