Electronics Design¶
Here is the group assignment for this week:
-
Use the test equipment in your lab to observe the operation of an embedded microcontroller (as a minimum requirement, you should demonstrate the use of a multimeter and oscilloscope)
-
Document your work to the group work page and reflect on your individual page what you learned.
For this week’s group project, we made use of the Oscilloscope and the Multimeter for observation. 🤗
The Oscilloscope¶
An oscilloscope is a tool that shows how voltage changes over time. It’s like a live graph of electricity, that lets you see what’s happening in your circuits. You can use it to check sensor signals, monitor motors and debug electronics (or just understand how a signal behaves over time).
To use it, you connect a probe to the part of the circuit you want to measure. The oscilloscope reads the voltage there and draws it on the screen as a waveform. The X-axis shows time, while the Y-axis shows voltage. By adjusting the scale and trigger settings, you can zoom in on small details or make fast signals stable enough to see clearly.
The oscilloscope that we have in our lab is the GDS-1202B GW INSTEK.
The GDS-1202B from GW Instek is a digital storage oscilloscope, which means it can store and display waveforms for later analysis, not just live signals.
The GDS-1202B has a variety of buttons and knobs to control how the waveform is displayed and measured:
- Power Button: Turns the oscilloscope on/off
- Vertical Scale Knobs (Volt/Div): Adjusts vertical scale (volts per division)
- Horizontal Scale Knobs (Time/Div): Adjusts horizontal scale (time per division)
- Trigger Level Knob: Sets the trigger level for synchronization
- Trigger Source Button: Selects the input channel for triggering
- Auto Setup Button: Automatically adjusts settings for optimal waveform display
- Cursor Measurement Buttons: Measure parameters like voltage, time, frequency, etc., using on-screen cursors
- CH1 / CH2 Buttons: Select input channels to display
- Run / Stop Button: Start or freeze the waveform
- Save/Recall Buttons: Save and recall waveform settings and data
- USB Port: Transfer and store data via USB
How it works:
Signal Input: The probes connect to the circuit and send the voltage signal to the oscilloscope.
Signal Conditioning: The oscilloscope adjusts the signal (makes it stronger or weaker) so it fits properly on the screen.
Vertical Deflection: Moves the waveform up and down according to the voltage — this is the Y-axis.
Horizontal Deflection: Moves the waveform across the screen at a constant speed — this is the X-axis (time).
Display: Shows the waveform on the screen so you can see what’s happening in the circuit.
Triggering: Keeps the waveform steady and aligned so repeated patterns or events are easy to study.
Our local instructors (Dawa and Yangtshel) walked us through the basic features of the Oscilloscope and the Multimeter 😃.
Steps to Use the Oscilloscope
1. Find Where to Connect
First, find the signal pin on the microcontroller that you want to measure.
Then find a GND (ground) pin nearby.
2. Connect the Oscilloscope
Clip the probe tip to the signal pin.
Attach the ground clip to the GND pin.
3. Set Up the Oscilloscope
Turn it on and set the voltage scale (for example, 1V per division).
Adjust the time setting so you can clearly see the signal.
Choose Auto trigger mode if you’re unsure.
4. Turn On the Circuit Make sure the microcontroller has proper power before checking the signal.
5. Look at the Signal
Watch the waveform on the screen.
Change the settings if the signal looks too small, too big, or unclear.
To test the oscilloscope, we used a sound sensor in the circuit and observed the waves.
The waves changed based on the sound:
Louder sound→ taller waves
Softer sound → shorter waves
High pitch → waves close together
Low pitch → waves farther apart
Different sounds → different wave shapes
Observing digital signals 😄
Observing analog signals 😃
Multimeter¶
A multimeter is a tool that measures different electrical properties in a circuit. It is like a Swiss army knife for electronics because it can do several things with one device.
A multimeter can:
Measure Resistance (Ω): Shows how much a component resists the flow of electricity.
Test Continuity: Checks if a wire or connection is complete; usually beeps if the path is okay.
Measure Voltage (V): Shows how much electric pressure is in a battery, sensor, or circuit.
Measure Current (A): Shows how much electricity is flowing through a circuit.
Some multimeters can also test diodes and measure capacitance.
To use a multimeter correctly, you need to connect it properly to your circuit!
Resistance Measurement (Ω)
To measure resistance, place the multimeter probes across the component while the circuit is turned off. This test tells you how much the component resists the flow of electricity.
For example, a resistor labeled 220 Ω should read around 220 on the multimeter.
Continuity Test
For continuity, place the probes across wires or connections to check if electricity can flow through. The multimeter usually beeps if the path is complete (low resistance).
For example, testing a wire will give a beep if it’s fine, or silence if the wire is broken.
Voltage Measurement (V)
To measure voltage, connect the red probe to the positive terminal (+) and the black probe to the negative terminal (–) across a battery, sensor, or circuit. This tells you how much electric pressure (voltage) is present.
For instance, a 9V battery should read around 9 V.
Current Measurement (A)
For current, the multimeter must be connected in series with the circuit, meaning you break the circuit and let the current flow through the meter. This measures how much electricity is flowing in amps.
For example, checking the current draw of a motor can tell you if your power supply is sufficient.
That is all for this week.