I made this little amplifier out of parts I pulled off of dead electronics so a more appropriate name would be a JunkAmp.
Here's a schematic I put together for people to reference. Download it by Right-Clicking then "Save as..." or "Save Link as...".
The image gets cutoff but just Right-click and "View Image" to see it all.
Here are the parts you will need.
LM386 Amplifier chip (8 pins)
10 ohm Resistor
10 microFarad (uF) Polarized Capacitor
220 microFarad (uF) Polarized Capacitor
0.047 microFarad (uF) Non-Polarized Capacitor
One Speaker: 8 ohm, 0.5 Watt speaker (I used a 8 ohm, 2 watt speaker in the video).
One 1/4 inch audio plug jack.
One 9 volt Battery.
One 9 volt Battery connector.
PCB Board
Wire. It's easier to use stranded wire, since it is more flexible.
Notes:
Polarized means there is a Positive and Negative end of the component. For the Capacitors, there is a white stripe on the side of the cylinder that leads from one of the leads (pin). That stripe indicates which side is Negative.
Since we are using a 9 volt battery for this project the Working Voltage of the Polarized Capacitors have to be higher than 9 volts, or else you will damage the Capacitor. The Working Voltage is usually written next to the White Stripe that I mentioned above and is just written as "9v" or greater.
The non-Polarized Capacitor does not have a polarity (+ -)so it doesn't matter which way it is positioned. Since the non-polarized capacitor is so small, the numbers on it will be written as "473" to indicate it's a 0.047 uF capacitor.
Edit: Jan. 17 2011
I've gotten a few questions about adding additional features and so I drew up a second schematic that shows how to add an LED for an indicator light, Power switch and a volume pot.
To add a little distortion, remove the 10 uF capacitor and replace it with a simple wire connecting Pin 1 and 8. The capacitor stabilizes the sound wave, but removing it will cause some distortion. Keep pin 1 and 8 connected though, this keeps the gain as high as possible.
If you have any questions, just email me at aDimWit@hotmail.com
Mini Guitar Amplifier by Justin Bread is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.
Both images embedded on this post are Attribution-NonCommercial Creative Commons licensed.
