Dynamo powered radio.

[louishenri]

Hey I need some information on how to build a dynamo powered radio.the radio currently works on 8 1.5v tipe D batterys.Any info is welcome.If possible a circuit diagram.

THANK YOU

 

[Nigel Goodwin]

No diagram needed - just ten D type NiMh batteries (you need ten to replace eight normal batteries), fed through a rectifier. Feed the rectifier from the dynamo, making sure the polarity is the correct way round (or it won't work, the rectifier stops it).

 

[louishenri]

ey NIGEL you perhaps know a website where i can find more information on the topic.

THANK YOU

 

[Hero999]

I don't see why you should need any batteries.

For a start, without a charging circuit or at least a current limiting resistor, the batteries would soon overcharge.

All you need is a voltage regulator, such as the LM7812 on the output of the rectifier.

You might need to add some overvoltage protection, depending on the maximum output voltage from the dynamo.

 

[Nigel Goodwin]

I don't see why you should need any batteries.

You're obviously reading his question differently to me?.

The best way it makes sense is a hand powered dynamo, so you need batteries to store the charge, and there's no problems with over charging.

 

[Hero999]

Yes I am, he didn't say anything about it being hand cranked, I thought it was going to be on a bike.

 

[Nigel Goodwin]

Yes I am, he didn't say anything about it being hand cranked, I thought it was going to be on a bike.

Same, thing applies to a bike, you need batteries for when you stop.

Although for a bike you've got a lot more potential for overcharging.

 

[Hero999]

Still, didn't think that was important, my mum's bike has dynamo lights which go out when she stops, except for a capacitor in the rear light which keeps the LEDs flashing for a minute or so.

 

[Nigel Goodwin]

Still, didn't think that was important, my mum's bike has dynamo lights which go out when she stops, except for a capacitor in the rear light which keeps the LEDs flashing for a minute or so.

Wouldn't keep a radio going though - but we're just speculating anyway, the OP has never clarified his question.