Electronics Question

Please post all questions and answers in here. This way people can easily see if someone else has the same problem.

Moderators: BeligerAnt, petec, administrator

Post Reply
razerdave
Posts: 1565
Joined: Mon Jan 02, 2006 9:40 pm
Location: Carterton, Oxfordshire
Contact:

Electronics Question

Post by razerdave »

Hi everyone

I'm not the most advanced builder about, but for my rebuild of Ying Yang I require a few electronic components, but I need some help straightening out fact from fiction.

The senario is this: I have a pair of pico servos for drive,a 7.4v lipo for power, and we know these do no go together very well, so I need to drop the voltage from 7.4 to 6 or below. Now, I have been told I can do this either with resistors or LED's. I have also been told if I wire resistors one way around they will drop voltage (Series) and another way will drop current (paralell), but I have also heard it is the other way around, so can someone tell me which is true ? I beleive LED's drop voltage but I wasn't sure if they could take the current, but I think they can take 130mA, but someone might know better than me.

Any help is greatly appreciated
Regards
Cavecrusher
Posts: 308
Joined: Sat Jul 19, 2003 12:00 am
Location: Netherlands

Post by Cavecrusher »

just get a 7806 and a capacitor, will get you 6v just fine
User avatar
BeligerAnt
Posts: 1872
Joined: Wed May 15, 2002 12:00 am
Location: Brighton
Contact:

Post by BeligerAnt »

Neither resistors nor LEDs are suitable for dropping the voltage in this case (or almost any case come to think of it!). As Tim says, use a 7806 voltage regulator IC. Add a 100nF (0.1uF) capacitor across the input (and another one across the output) and you have a pretty good solution.

Under heavy load you may not quite get 6V, but you probably won't notice. If you can find a low dropout voltage (LDO) regulator it will work a bit better, but you need to make sure you use the correct capacitors with it (otherwise they make very good oscillators! :( )
Gary, Team BeligerAnt
User avatar
harveyandpuma
Posts: 32
Joined: Sat Dec 30, 2006 10:23 am
Location: spain

Post by harveyandpuma »

hi i just joined and i am waiting for my antweight order to arrive.

i ordered it off robot market place and ive been waiting for about 4 weeks for it to come.

is this because i live in spain if it is how long will it take.


thanks

harvey
Post Reply