Build Your Own Function Generator! (Part 2) | XR2206 DIY

Foundation Verse

Psalm 41: 1–2 KJV

1 Blessed is he that considereth the poor: the Lord will deliver him in time of trouble.
2 The Lord will preserve him, and keep him alive; and he shall be blessed upon the earth: and thou wilt not deliver him unto the will of his enemies.

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Overview

Welcome to Part 2 of the XR2206 Function Generator Build!

In this lesson, we finish assembling the function generator kit, install the final components, place the XR2206 IC into its socket, mount the board into the clear case, and finally test the output using the DSO138 oscilloscope.

By the end of the video, we successfully generate and view a clean sine wave signal.

Watch the Video:

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What We Finished

In this part of the build, we installed:

• Non-polarized capacitors
• IC socket
• DC power jack
• Jumper pins
• Output terminal block
• XR2206 IC chip
• Clear case hardware
• Control knobs
• Waveform and frequency jumpers

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Important Build Notes

Non-Polarized Capacitors

The small capacitors used in this section are non-polarized, meaning they can be installed in either direction.

Even though polarity does not matter, I lined up the printed numbers in the same direction to keep the board looking clean inside the clear case.

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IC Socket

The XR2206 chip itself does not get soldered directly to the board.

Instead, we solder the IC socket first, then insert the chip later.

This helps protect the IC from soldering heat and makes replacement easier if needed.

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Watch the Notch

The IC socket and the XR2206 chip both have a notch.

That notch should match the marking on the circuit board silkscreen.

This helps ensure the chip is installed in the correct direction.

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Be Careful with Plastic Connectors

Parts like jumper headers and terminal blocks are held together with plastic.

Too much heat from the soldering iron can soften or melt the plastic, causing the pins to shift.

Tip:

Solder quickly, use just enough heat, and inspect the part afterward.

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Soldering Lesson Learned

Some pads were harder to solder because they were connected to larger copper areas.

Large copper areas can pull heat away from the soldering iron, making the joint take longer to heat.

This is common with larger traces or ground-plane areas.

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Cleaning the Board

After soldering, the board was cleaned with electronics cleaner and a small brush.

This helped remove flux residue and made the board look cleaner and shinier.

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First Power-Up

After the XR2206 chip was installed and the board was cleaned, it was time for the first power-up.

The function generator was powered using a 9V power supply.

Good news:

No smoke!

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Case Assembly

The board was placed into the clear acrylic case.

The knobs were installed on the control shafts, and the jumpers were set for:

• Sine wave output
• 10 Hz to 100 Hz frequency range

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Oscilloscope Test

To test the function generator, we connected it to the DSO138 oscilloscope.

The function generator output was connected to the oscilloscope input:

• Function generator ground to oscilloscope ground
• Sine wave output to oscilloscope signal input

After adjusting the amplitude and oscilloscope settings, we successfully displayed a sine wave.

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Measuring the Signal

The oscilloscope was set to:

5 ms per division

One complete waveform took about:

2 divisions

So the period was:

2 × 5 ms = 10 ms

Frequency is the inverse of period:

1 ÷ 0.010 seconds = 100 Hz

So the output signal was approximately:

100 Hz

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Voltage Measurement

The waveform was adjusted to about:

4 volts peak-to-peak

That means the signal went approximately:

• +2V above zero
• -2V below zero

for a total swing of about 4V peak-to-peak.

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Final Result

The XR2206 function generator worked!

We successfully generated a sine wave, adjusted the amplitude, changed the frequency, and viewed the signal on the oscilloscope.

This is a great tool for future lessons because we can now use it to feed signals into other circuits.

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Coming Next

In the next lesson, we’ll use this function generator to explore:

Small Signal Amplifiers

We’ll take a waveform from the function generator, feed it into an amplifier circuit on a breadboard, and see if we can make the signal larger.

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Video Summary

In this video:

• We finished the XR2206 function generator kit
• Installed the final hardware
• Inserted the IC chip
• Powered up the circuit
• Installed the case
• Connected it to an oscilloscope
• Verified a working sine wave
• Measured approximately 100 Hz output
• Prepared for the next amplifier lesson

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Thanks for spending time with me on this function generator build.

I think it’s time to go to the lab!