Sparkfun mono audio amplifier

Components & Accessories Input Devices
1

I’m attempting to use the audio amplifier circuit board

I have a diagram for my attempt to set it up

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The function generator on the right is my arduino set to make a square wave on pin 11. The ground pin on the right is the ground pin of my arduino. I set the power supply to 5V and connect it to positive and negative power pins. I believe the “S” stands for shutdown and I think I’m supposed to set that to 5 V So I just connected it in parallel with the “+” of the power supply. I have my oscilloscope + and - probes hooked up to the + - probes of the “out” holes.

I don’t know what the holes labeled “VOL” are for so I didn’t hook them up to anything.

I’m not seein the square wave I expect on the output. Can you see what’s wrong from my diagram?

Edit: I think I figured out the problem. I just attached the oscilloscope probes directly to the output wires. When I change things so that the output wires are connected to ground and I connect the output probes to them in parallel I’m seeing the output now.

Although, it doesn’t appear to be scaled so there’s still something off.

2

Hi Onyebuchi ( @Rioghasarig ) ,

Your circuit diagram does not look correct. For the Power (PWR), you have no Ground (GND / 0V) connection.

Your connections should be:

OUT + : output to speaker +ve (red terminal)
OUT - : output to speaker -ve (black terminal)

PWR + : power supply +ve (5V)
PWR - : power supply Ground / GND / 0V

You can leave the Shutdown (SDN) pad open. It has its own pull-up to power supply +ve.

You can leave the Volume (VOL) pads open. By default, the full input signal is fed to the amplifier through the solder jumper SJ1.

You probably do not need to add your own resistors and capacitors on the signal input. These are already included on the circuit board.

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I hope this helps,
Paul

3

Thanks, I’ll try and rewire it tis weekend.