Instructables

How do you reduce 6 volts to 4.5 volts?

I am working on a toy truck that will play music, have headlights that will light and a gear system that will lift the truck up and down when a switch is pressed. The music (took from a stuffed keychain pig) and lighted headlights (Blue LED) work using 4.5 volts. My gear system use to use 4.5 volts to lift the truck, but now it won't do it. In order to lift the truck I have to increase the voltage power to 6 volts. If I increase the power of the gear system to 6 volts or more then it will fry my music and lights (however, I can make adjustments to the LEDs with resistors). The higher the volts are for the gear system, the easier it is to lift the truck. Maximum volts for the system are 12 volts. I know lifting the truck puts a strain on the system but the more power I give it; the better it can lift the truck. My goal is to use one power source and one switch. I thought I could use to different power sources (6 v and 4.5 v) and connect it to one switch, but I think it will fry of my music and lights. My question is: How do I reduce 6 volts to 4.5 volts, using 6 volts as my main source and connect everything to one switch? If I can get this figured out then this will help me with future project, where I need to use voltage reduction (or is it called voltage regulator). My knowledge of electronics is very low or enough to get me in trouble, which it has done. I am familiar with a few basic electronic terms and formulas. I will except and appreciate any help, ideas, diagrams, etc. Please use layman terms.

 When you say it used to work on 4.5 volts, but now it doesn't, it sounds like you are losing power somewhere. If it used to work at 4.5 v, it still should. Before setting up a dual 6 and 4.5 v system, check the following:

It is possible your batteries are weak or too small. Try replacing the batteries. If that doesn't help, try the next larger diameter batteries (like C if you were using AA)--they can deliver more power.

Make sure you have connected the motor, lights, and sound in parallel, not series (search "series parallel circuits" if you are not sure about the difference). A series hookup is wrong because each item in the circuit sucks power from the others.
mates (author)  cyberpageman4 years ago
Thank you, thank you, thank you for your comments!  I now see my mistakes and understand how putting everything in series drained my gear system.  Once I disconnected everything and applied power to the gear system only, it lifted the truck without any problems.  So I will put everything in parallel and try it.  I may also increase the battery size to C.

Now a sad note.  I killed my music card.  It's death may have occured when I swtich from AA to C batteries or I hooked it up to my switch wrong.  See I told you I was good at frying circuits.  The card sounds like it is singing in either slow motion or sound like Alvin and the Chipmunks.  Or it will start off normal and go into slow motion phase or chipmunk phase.  Now my search is to find the same type of music, which I took out of a stuff pig keychain.  The music by the way is "Born to be Wild" which would have been great with my truck.  Is there anyway to save my card?

Thanks again for your comments.

luxstar1 year ago

Here is an instructable using a DC to Dc converter:

 

 

 

http://www.instructables.com/id/93-efficient-DC-to-DC-Converter/

The data sheet says the input voltage can be 4.5 to 14 volts. The output can be adjusted from one half volt to 6 volts. Murata makes several different devices for different current / wattage requirements;

 

 

http://www.futureelectronics.com/en/Search.aspx?dsNav=Ntk:PlainTextSearch%7coktr%7c3%7c,Ny:True,Nea:True

LM317 adjustable voltage regulator + Two resistors Steve
mates (author)  steveastrouk4 years ago

Hmmmm....How do you put it together and make it adjustable to your voltage output?  I have an idea on how the 78XX voltage regulators work but not a LM317.  Is there a good LM317 circuit or circuit diagram from Instructables that will help me understand how to use it?  This could help me with other projects as well.

Thank you.

Try this.<br /><br />http://www.electronics-lab.com/articles/LM317/index.html<br /><br />Application circuit and component calculator !<br /><br />
mates (author)  steveastrouk4 years ago
Wow!  I love it!  A circuit and component calculator.  This what I need.  I'm also learning basic electronics to get a better understanding on how these circuits work.  Using the calculator does help but you still need a basic understand of the circuit.

Thank you very much.  This is what I like about this site, Instructables community.

Take care.
Re-design4 years ago
Gears need greasing, aligning or cleaning.  I would look to a mechanical problem stealing power somewhere.
mates (author)  Re-design4 years ago
I cleaned it and regreased it just in case dirt and grime was the problem.

Thank you for your comments
kacarot4 years ago

untitled.bmp
The two 10K resistors and the 22 K in parallel make about 10.5 K. The 1 ohm in series doesn't add much. That part of the circuit passes only about 0.01 mA which isn't enough to drive the motor.

But it is nice of you to have provided a circuit. It's more than the rest of us did.

mates (author)  kacarot4 years ago

This is something I will try with another circuit I am working on which involves a music card.  Thanks!