I need help regulating the DC voltage in a circuit

[Metalio]

I do not have much know-how in the electronics world but I would really appreciate some help. I am fitting some EL wire on to my bicycle and making it pedal powered. I have decided to use an old printer motor to produce the electricity and did a small test and received about 3-17v and I am pretty sure if I go really fast I might get about 20v. I need to make it 12v DC so it will work with my transistor, but because the voltage would be fluctuating I couldn't use just one resistor. What could I use to make the changing voltage a constant feed of 12v DC?

Thanks in advance.

 

[davenn]

with any form of generator like that it will be next to impossible to get a constant voltage because of the wildly varying speed of rotation of the generator motor

The best you could maybe do would be to use that voltage through a charging cct to charge a battery pack, then run the transistor off a regulated output of the battery

you had better clarify what "my transistor" is

Dave

 

[ericgibbs]

I do not have much know-how in the electronics world but I would really appreciate some help. I am fitting some EL wire on to my bicycle and making it pedal powered. I have decided to use an old printer motor to produce the electricity and did a small test and received about 3-17v and I am pretty sure if I go really fast I might get about 20v. I need to make it 12v DC so it will work with my transistor, but because the voltage would be fluctuating I couldn't use just one resistor. What could I use to make the changing voltage a constant feed of 12v DC?

Thanks in advance.

You could use a 7812 inexpensive 12V regulator IC.
To get a constant 12Vout, you would need to pedal hard enough to produce 15V on the input to the 7812.

What is the volts/current specification of the EL wire.??

 

[Metalio]

okay, thank you for your help.
My transistor requires 12v DC from a standard car battery.
I don't know much about the EL wire but I think it requires about 100-130v AC and 400-4000hz.
I think I will buy that 12v regulator, seems like it would work. But if it doesn't work, I will try that other idea with the battery.

 

[ericgibbs]

okay, thank you for your help.
My transistor requires 12v DC from a standard car battery.
I don't know much about the EL wire but I think it requires about 100-130v AC and 400-4000hz.
I think I will buy that 12v regulator, seems like it would work. But if it doesn't work, I will try that other idea with the battery.

When you say 'transistor' is that the module that drives the EL and it requires a 12V input.??

 

[DerStrom8]

I would definitely use the power produced by the bike to charge a battery pack, and then connect the battery to a 7812 voltage regulator. That would probably be the simplest way to do this.
Der Strom

 

[MikeMl]

The ideal solution would be to use a step-up switch-mode power converter IC that makes a constant 12V starting with a 6V battery pack. The reason to use the 6V battery pack is because your generator can be producing useful output even when pedaling slow. A simple low-dropout regulator could be used to disconnect the battery from the generator when the battery is fully-charged (to protect the battery).

 

[kumailbutt]

You can charge a battery using pedal and use 7812 regulator. But it is difficult to get sufficient current using printer motor.

 

[Grossel]

Hi. Is this something stationary, or is it mounted on a bicycle or something?

Reason why I ask is that If it's stationary, you could always use a 12V battery* and a regular (or multi phase) diode rectifier between your printer motor and the battery to maintain the batteries charge.
Also you can add a two-diode rectifier, combined with a cap to get twice as much output voltage, so that the battery will charge at lower speed too.


* Like the battery in cars, but suitable to other purposes than deliver power to start a fuel engine - don't know the english term of such batteries, but sure you know what i'm talking about.


[edit]
Drawing attached

 

[Metalio]

the motor would be attached to the bike wheel so when it's moving, it's making electricity.

Yes, the transistor is what takes the 12v DC and converts it to AC at the requirements for the EL wire. I could also get one with a lower voltage (like 3v from two AA batteries) but I already bought the 12v one.

I'm not sure but I think I was not too clear with my idea. I want to make it so that when I pedal, the lights turn on, and when I stop, they turn off. the problem is the motor is producing enough voltage to power the transistor but it can give out too much if I go fast, and I want to go fast. I was also thinking that maybe a capacitor could also be added to keep the voltage at 12 if I slow down for a short time and speed back up. I might even install a voltmeter between the motor and transistor to keep an eye on the voltage.

if all else fails I'll probably go with MikeMl's idea.

 

[atferrari]

Moderator please delete this.

 

[ronv]

Maybe something like this would work for you.

**broken link removed**