A simple power supply?

[GreenAce92]

I'm working on an experiment that requires a variable voltage that I can easily control by turning a dial.

I'd like to make this a simple/small power supply requiring one 9V battery and a bread board plus the other components.

All it has to do is this

9V > Dial > leads

I don't know any exact power output that I would like yet but then this power supply will also need to get connected to an H-bridge which will then be connected to a soleonid.

But it's all going to very small

Just a side note, any idea where I can get cheap easy to get cylindrical magnets say 1/4 - 3/8 diameter with a hole in the middle?

Thanks for the help

One more thing, how reliable are these needle voltmeters?

 

[davenn]

what range do you want to vary over specifically ?
keeping in mind that a 9V battery with a LDO Low Drop Out regulator is
going to give you a max of ~ 8 - 8.5V
depending on the current draw of your project, you may find the battery has a relatively short lifespan

I know where to get cylindrical magnets, they just dont have holes up the middle
... if thats for your solenoid ?? then you dont want magnets you need to wind a coil on a former to make an electromagnet (or buy one)

needle voltmeters have been used "since Adam was a boy" no problems

Dave

 

[GreenAce92]

I'm trying to build one of these (attached images)

A small scale experiment, I just want to try and disprove people about solenoids being used to power ornithopters

The most common thing that comes up is

"..you don't have enough torque since magnetism is going through the air..."

or

"... you don't generate enough torque since they're so far apart..."

or just that solenoids don't have enough power to mass ratio to keep a bird in the air.

Granted I only intended this type of a powerplant for micro vehicles

All I want to do is to have a small power plant to play around with safely

I supposed I should just opt for a plug in the wall type

How about this... let's change it to

Using a DC 12.5V 6A power supply

I'd like to step it down to be used with micro enamel wire

What I'm trying to do is have a hollow core solenoid with a hovering (not really hovering) magnet so it's like a piston, then I transfer this motion to flap wings.

How do you know what a wire is rated for?

I am familiar with gauge and strands/non-strand

But which is better?

Could you give me a simple low down?

I'm at a different computer so I cant attach the images

Here they are by separate links

http://www.rcgroups.com/forums/showpost.php?p=18722050&postcount=2

http://www.rcgroups.com/forums/showpost.php?p=18742419&postcount=14

and I appreciate your help, thanks!