# The Naked Scientists Forum

### Author Topic: How do I build a dynamo with a specific output voltage?  (Read 593 times)

#### GrajScience

• First timers
• Posts: 1
##### How do I build a dynamo with a specific output voltage?
« on: 13/01/2016 17:50:54 »
I'm having a hard time finding information about dynamo construction.

I know how to build a simple generator.  Thanks 8'th grade science.

What I am having difficulty with is finding out how to build a dynamo with a specific output voltage.

I can buy one on the internet. Hand Crank 110v ac generators are all over the place.

But I want to build one with my kids in the garage.

If someone could just help guide my questions, so that I know how to ask the question in the proper format to get me to the information I am looking for, that would be awesome.

Is it primarily based on the RPM's?  The number of magnets? The number of windings?

Any help would be appreciated.

Thanks!
« Last Edit: 13/01/2016 20:17:57 by chris »

#### RD

• Neilep Level Member
• Posts: 8088
• Thanked: 51 times
##### Re: How do I build a dynamo with a specific output voltage?
« Reply #1 on: 21/01/2016 00:09:23 »
You need a voltage-regulator circuit ...

http://www.instructables.com/id/Voltage-Regulated-5-V-Bicycle-Dynamo-Light-USB/

NB: Human-powered electricity is ecologically unsound ... http://www.cnet.com/news/human-energy-harvesting-a-very-silly-idea/

#### alysdexia

• Sr. Member
• Posts: 121
• Thanked: 3 times
##### Re: How do I build a dynamo with a specific output voltage?
« Reply #2 on: 23/01/2016 06:17:39 »

You'll need to go by the rated B strength in gauss or tesla if you don't own a meter, then take the sectional area of the wire itself (I think), rather than the loop, to find flux.

#### The Naked Scientists Forum

##### Re: How do I build a dynamo with a specific output voltage?
« Reply #2 on: 23/01/2016 06:17:39 »