- #1
MJay82
- 42
- 0
For my physics class this semester, we had a broad-ranged project to work on. Basically "anything related to physics" was the category. Initially I had wanted to build a percussion synthesizer circuit, but all I could manage to do was pick up a radio station 10 miles from my house, so I quickly switched gears so I had something to turn in.
I decided to build a lemon battery to power an LED, and do some experimentation. Out of curiosity, I picked up some limes too, and some apple cider vinegar and some balsamic vinegar. I made a few batteries and used my multimeter to measure the voltage of each battery. Then I started trying to light the LED (10 mA). In series, I added the batteries and ended up with a final voltage of 3.5 volts. I thought that this would be plenty to power an LED, but I found that it wasn't. Using my multimeter again, I measured the current produced by the batteries - 0.1 mA out of 3.5 volts! I was disappointed, but also intrigued by the discovery. I started thinking about Ohm's law, and here I get to my question:
If I were to use R = V/I, will this resistance be the internal resistance of the battery?
Also, what might be a way to increase my current with these food-related batteries? I tried V8 and Diet Coke - they both produced considerably more current than the lemons and vinegars, but still not enough to power the LED. When I added the V8 and Diet Coke batteries in series, the battery power was enough to get a flicker out of the LED.
I've got some Gatorade and wine that I hope to experiment with tonight. I would really like to get a big enough current out of these novel battery sources to brightly power the LED. Is there a way?
Additionally, my understanding of LEDs in series says that if I can power one LED, then since current will be conserved across series connections, I should be able to power a whole row of LEDs, expecting a voltage drop of about 2V across each LED.
I hope someone can help - this project is due on Wednesday and I'll have almost all day tomorrow to devote to polishing it up. Thanks in advance!
-Michael
I decided to build a lemon battery to power an LED, and do some experimentation. Out of curiosity, I picked up some limes too, and some apple cider vinegar and some balsamic vinegar. I made a few batteries and used my multimeter to measure the voltage of each battery. Then I started trying to light the LED (10 mA). In series, I added the batteries and ended up with a final voltage of 3.5 volts. I thought that this would be plenty to power an LED, but I found that it wasn't. Using my multimeter again, I measured the current produced by the batteries - 0.1 mA out of 3.5 volts! I was disappointed, but also intrigued by the discovery. I started thinking about Ohm's law, and here I get to my question:
If I were to use R = V/I, will this resistance be the internal resistance of the battery?
Also, what might be a way to increase my current with these food-related batteries? I tried V8 and Diet Coke - they both produced considerably more current than the lemons and vinegars, but still not enough to power the LED. When I added the V8 and Diet Coke batteries in series, the battery power was enough to get a flicker out of the LED.
I've got some Gatorade and wine that I hope to experiment with tonight. I would really like to get a big enough current out of these novel battery sources to brightly power the LED. Is there a way?
Additionally, my understanding of LEDs in series says that if I can power one LED, then since current will be conserved across series connections, I should be able to power a whole row of LEDs, expecting a voltage drop of about 2V across each LED.
I hope someone can help - this project is due on Wednesday and I'll have almost all day tomorrow to devote to polishing it up. Thanks in advance!
-Michael