Sunday, May 19, 2013

Dynamo attempt1

I havent fiddled with anything for a long time. Trying to build a dynamo has been on my mind for years. But forgetful me forgot to buy electronics stuff like resistors etc from good old Rajeev Electronics when I went to Pune. The result? What I would have paid a rupee for in India for say a LED, i paid a dollar or two here.

Anyway, here's my dynamo trial.
All equipment from Radioshack.
Magnets: are a set of 4 disk magnets
Coil: Is a wire, more about that later.
LED: Red led, 1.8 V (I am like whaaaaaaaaaaaaaaat!! I am damn sure I have used a 1.2 V white LED in India. With the tiny magnets I am not sure how much voltage is going to be generated, and the 1.8 V led is the least voltage one I could find in Radioshack.
Resistors: My calculation is 1.8V / current needed by LED. My friend (will be called MF ahead) berates me, it should be (system vtg - 1.8) V / current needed. Eeks :P

MF's try 1, what MF calls simulation: Unstripped wire wound against a reynold's pen, then moves the magnet around it. LED doesnt light. MF gives up. Now it is my turn to berate MF. Hah! Revenge complete. I remind the stupid MF, that even if LED doesnt light, theoretically Mr. Faraday can prove voltage generated using a DMM. Voltage created = 0.8 V.

Deepika's try 1: I strip the wire. My logic is that we need uninsulated wire. MF wins back the chance to call me stupid. Points out that electrical insulation and magnetic insulation are 2 different things. My simulation doesn't light the LED either.
Deepika's try 2: So to increase the voltage generated we either need to use a stronger magnet = more money outta pocket, or increase the number of turns of coil. (accompanied by a "Oh I am so smart that I remember my 12th standard Physics" smile)
Ok so electrical simulation != magnetic simulation. I use the whole 150 ft of the wire, thankfully American smartness is such that the other end of wire is accessible in the spool.
Voltage generated is still around 0.8 V.

I say that we need a better coil or use a legit inductor. Maybe i need to strip out the wire and wind it real well with a extremely thin layer of insulation. I can think of nail paint as maybe something that I can coat thinly enough on the coil. Obviously, I can just go and buy a legit inductor, but this dynamo building is supposed to be hands on tinkering that I have not done in a while.

Now that I think about it, I picturize a transformer. It is wound around iron? Certainly it is very heavy to hold. So instead of a reynold's pen, let me try wrapping the wire around a piece of iron.

Basically, MF's idea of simulation sucked. If I had started directly, I would have wrapped the wire across the cycle metal, and there is a possibility that it would have worked. 

अतुल आत्ता वाचून डोकं आपटत असेल, but ever since Atul has told me about the foxhole radio, I am enchanted by it. If the soldiers scouring regular household stuff could build a radio (doesnt that need an antenna = something to resonate = a coil somewhere? ), surely I can make a coil that works.
Take-aways from the attempt:
1. electric insulation != magnetic insulation
2. inspired me to make a coil.. This is what I love about electronics, it gives you a high. Till I recover from my coil-making obsession..adios!

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