Intro: Simple OP Amp Radio
This is just what you think it is, a radio made with an op amp. This is just as accidental and simplistic as my other radio instructable (the 555 radio) and actually made me ask myself if I was just an RF magnet or something. There is only about a handful of parts you need and while somewhat pricey they are all obtainable at Radioshack. So if you feel like making your own simple radio for field reception. This is a good choice (if you've seen my 555 radio instructable you'll bee happy to know I was able to get two decent signals from two stations this time). For those who want to see the 555 radio follow this link here: https://www.instructables.com/id/555-timer-radio/ - otherwise let's get to building!
Step 1: Parts You Will Need
Alright all you'll need for this project are the following:
x1 LM386 op amp IC chip
x2 1000 microfarad capacitors (any capacitor works but it's louder with these)
x1 100 microfarad capacitor
x1 8 ohm speaker
x1 9 volt battery
x1 project board
some wire (I used about a foot and a half)
optional - a wire parabola (such as a mini fan cage, a colander, etc.)
And that's it. Of course this isn't a crystal clear signal, but I think you'll be surprised how easily you can understand the voices and the music is pretty clear too, there is some minor static but after listening for a while it's barely noticeable.
Step 2: Building in 1 Step!
Simply put this circuit doesn't take much to make. It surprised and annoyed me because it gave me a radio signal when I was trying to make a backpack boombox circuit, so I fiddled with this and I present it to you here. And here are the 4 steps to creating this circuit.
(Please realize that when I talk about the pins I refer to the pins in counter-clockwise order from the clocking mark (probably an indent or circular mark at one end of the chip near pin 1. Pin 1 is the most counter-clockwise going down the left side to pin 4 and continuing at the bottom of the other side at pin 5 going up the right side to pin 8.)
1. Plug in your op amp and add a jumper wire from pin 6 to power and a jumper from pin 4 to ground.
2. Plug another jumper wire from pin 2 to ground and plug your antenna into pin 3.
3. Plug your 100 microfarad capacitor's positive side into ping 7 and the negative side into ground. Plug one your 1000 microfarad capacitor's positive side into pin 1 and the negative side into pin 8. The other 1000 microfarad capacitor's positive side into pin 5 and the negative side into a blank space on your board. Plug your speaker's positive side to the last capacitor's negative side and the negative side of your speaker to ground.
4. Plug in your battery's terminals to their respective rails (red to power, black to ground)
and then (if you have a switch added) turn it on and simply move your antenna wire around to get your signals. If you want a good signal using a metal fan cage works very well.