Speed of Dark Blog

If you type “Audio Amplifier” into Google, you’re going to get circuits that the beginner (and even mildly serious) hobbyists can’t easily build, let alone understand.  So, stopping by my local Radio Shack, I picked up an LM386 Low Voltage Audio Amplifier.  A little poking around and I found National Semiconductor’s data sheet, showing a schematic that requires only 5 components for a gain of 20, and 7 for a gain of 200.  Being the skeptical man I am, I built the 5 component variation and plugged in my MP3 player.  I used a 9V wall transformer for power.  Lots of noise resulted.  Well, I discovered the need for a 6th component:  Big capacitor on the power supply.  It’s usually a rule of thumb to have one anyway, even if you’re running off of a stable supply like a battery. This circuit is simple and effective.