Electronics Design¶

Summary¶

Group assignment¶

Multimeter¶

We used a multimeter from the company UNI-T to measure voltage, current, and resistance. It’s a convenient, compact device with a backlit display, which makes it easy to work in dark or low-light environments.

Voltage and Current Measurement¶

Objective¶

The goal of this experiment was to measure voltage and current in a simple LED circuit using a bench power supply and a digital multimeter. This was done to verify the correct operation of the circuit and validate theoretical calculations using Ohm’s Law.

Equipment Used¶

Bench DC Power Supply (WANPTEK)
Digital Multimeter
LED
Arduino board (as test platform)
Connecting wires

Voltage Measurement¶

The power supply was set to approximately 2.4V.

We measured the voltage using a digital multimeter connected in parallel with the load.

Results:

Power Supply Voltage: ~2.4V
Multimeter Voltage Reading: ~2.44V

This confirms that the output voltage of the power supply is stable and accurate.

Current Measurement¶

To measure the current, the multimeter was connected in series with the LED circuit.

The power supply display showed:

Voltage: 2.4V
Current: ~0.14A

The multimeter confirmed that the circuit was drawing current within safe operating limits.

Theoretical Background¶

According to Ohm’s Law:

[ I = \frac{V}{R} ]

Where: - ( I ) is current (Amperes) - ( V ) is voltage (Volts) - ( R ) is resistance (Ohms)

The measured current matched the expected behavior based on the applied voltage and resistor value in the circuit.

Observations¶

The LED operated correctly.
The measured voltage was consistent with the power supply setting.
The current was within safe range for the LED.
The circuit behaved as expected.

This test confirmed that the circuit design and component selection were correct.

Oscilloscope Signal Measurement (Brushless Motor)¶

Objective¶

During this experiment, we used a two-channel digital oscilloscope to analyze the signal generated while driving a brushless motor used in a drone system.

The goal was to observe the waveform characteristics and verify proper motor control signal behavior.

Equipment Used¶

Two-channel Digital Oscilloscope
Brushless DC Motor (BLDC)
Electronic Speed Controller (ESC)
Power Supply
Signal source (motor controller)

Signal Measurement¶

The oscilloscope probes were connected to:

Channel 1 – Motor control signal
Channel 2 – (optional) Power line / comparison signal

The oscilloscope allowed us to visualize the electrical waveform in real time.

Observations¶

The motor control signal was a PWM (Pulse Width Modulation) signal.
The frequency and duty cycle changed depending on throttle input.
The waveform shape confirmed correct ESC operation.
The signal amplitude remained stable during operation.

The two-channel oscilloscope allowed us to compare signals simultaneously and analyze timing behavior.

Why Oscilloscope is Important¶

Unlike a multimeter (which measures average voltage or current), an oscilloscope allows us to:

Visualize waveform shape
Measure frequency
Measure duty cycle
Detect noise and signal instability
Analyze switching behavior

This is especially important when working with high-speed systems like drone motors.

Logic Analyzer Signal Analysis¶

Objective¶

In addition to using a multimeter and oscilloscope, we also worked with a logic analyzer to analyze digital signals in the system.

The goal was to capture and inspect high-speed digital communication and PWM signals generated during motor control.

Equipment Used¶

Logic Analyzer
Brushless DC Motor (BLDC)
Electronic Speed Controller (ESC)
Microcontroller (Arduino / Flight Controller)
Power Supply

Why Logic Analyzer?¶

A logic analyzer is used to analyze digital signals, unlike:

Multimeter → measures voltage and current
Oscilloscope → visualizes analog and mixed signals
Logic Analyzer → captures digital signal timing and communication

It allows us to:

Observe HIGH / LOW transitions
Measure signal timing
Decode communication protocols
Analyze PWM and digital control signals

Signal Capturing¶

The logic analyzer was connected to the control signal line between the microcontroller and the ESC.

We observed:

Digital PWM pulses
Duty cycle variation
Signal timing changes during motor speed adjustments

The analyzer helped verify that the control signal was correctly generated.

Observations¶

The signal switched cleanly between HIGH and LOW states.
The pulse width changed according to throttle input.
No significant signal noise was observed.
Timing behavior matched expected PWM characteristics.

This confirmed proper digital control of the brushless motor.

Comparison of Tools¶

Tool	Purpose
Multimeter	Measures voltage and current
Oscilloscope	Shows waveform shape and frequency
Logic Analyzer	Captures digital timing and protocol data

Conclusion¶

During this lab session, we used three essential electronic measurement tools: a multimeter, a two-channel oscilloscope, and a logic analyzer.

First, we measured voltage and current using a digital multimeter and a bench power supply. This allowed us to verify that the circuit operated within safe electrical limits and matched theoretical calculations based on Ohm’s Law.

Next, we analyzed the PWM signal driving a brushless DC motor using a two-channel oscilloscope. This enabled us to observe waveform shape, signal amplitude, frequency, and duty cycle in real time. The oscilloscope confirmed stable and correct motor control signals.

Finally, we used a logic analyzer to inspect digital timing behavior. This allowed us to capture HIGH and LOW transitions of the control signal and verify correct PWM timing and digital communication characteristics.

By combining these three tools, we gained a deeper understanding of both analog and digital signal behavior. This hands-on measurement process strengthened our debugging skills and validated the proper operation of the electronic system.

These measurement and analysis techniques are fundamental in embedded systems development, drone electronics, and real-world hardware prototyping.