Capacitors

[danthegeek]

Hey everyone, I have a quick question. How would I convert 5 volts from the Power Supply into 12 volts? I believe you would use a capacitor but which kind? I ask because, I have been helping a member with the remote start for his computer. However, he can only find 12 volt door chimes, not 5 volt. It needs to be 5 volts to run the PS when the system is turned off.

Thanks again

-danthegeek

[Dilphat]

Thanks for the help dan. I hope someone replies to this.

[r0adawg]

don't know if this will help or not... but it looks like it will foot the bill

from what I read, it can act like a setup or stepdown converter...
here is hoping that you don't need that much mili-amps in your project, looks like about 90mA is about what this little guy can do...

http://tinyurl.com/yudf7k

check out the pdf --> "LT1073 Specification Sheet"

and have a look.... if this works... I'm thinking you will want part # LT1073CN8-12


looks to be about 3.67 each min 2/order..

other option is to request samples. the least they will do is say no....

[crazybillybob]

Dan,
I'm going ask a few Q's then Explain what a cap does...Then hopefully we can get this working:)

When you say he can only find 12V door bells We're talking about the wireless movable kind (as they work best for remote starts). Normally they run on AA batts not wall plug. If that's what we're talking about can you give me the model # and mfg... Also give me the location of the user your working with (Ie. USA, UK,etc) this helps with what they have locally and voltages to work with. I think that you've just got a simple misunderstanding... or not :) With that said the lesson.

A device that consists of two conductors (such as parallel metal plates) insulated from each other by a dielectric. A capacitor introduces capacitance (ie, the ratio of the charge on one of the conductors of a capacitor to the potential difference between the conductors) into a circuit, stores electrical energy, blocks the flow of direct current, and permits the flow of alternating current.
www.csa.com/hottopics/mems/gloss.php

In simple terms a Cap charges up to the line voltage and attempts to keep the line at that voltage.....So when the voltage drops it looses some of it's charge to bring the line up to the caps level.

For what you want let 5V drive 12V device you need what's called a voltage doubling circuit (or a voltage doubler) Google should get you a slew of schematics for them. the thing to keep in mind here is that when "stepping up " Voltage you lower current in this case by half so if you had 5V with 1A to start with you'll get 10V with less the 500Ma in doubler..

I really don't think you need to go this route.... The 5V door bell isn't an in dangered Critter.... I'll see if I can't pop down to my local Home Despot and get some stock #'s for you. It'll help.


Sorry for the long post, Electronics talk always gets me GEEKED :D

CrazyBillyBob

[crazybillybob]

Ok,
I hit Lowes at lunch and found this guy Heath Zenith Basic Series Wireless Door Chime (http://www.amazon.com/Heath-Zenith-Wireless-Off-White-SL-6153-C/dp/B0002YSLC8/ref=sr_1_2/105-9914421-2902839?ie=UTF8&s=hi&qid=1188245055&sr=8-2) it's $19.87 Runs on 4 D batteries (6V...will work with 5V). Looks like it should do the trick. Home Despot also has a similar model. Have heard a tail that Wal-mart even carries something similar too. So if your in the US you should be ok.


CrazyBillyBob

[danthegeek]

Ok,
I hit Lowes at lunch and found this guy Heath Zenith Basic Series Wireless Door Chime (http://www.amazon.com/Heath-Zenith-Wireless-Off-White-SL-6153-C/dp/B0002YSLC8/ref=sr_1_2/105-9914421-2902839?ie=UTF8&s=hi&qid=1188245055&sr=8-2) it's $19.87 Runs on 4 D batteries (6V...will work with 5V). Looks like it should do the trick. Home Despot also has a similar model. Have heard a tail that Wal-mart even carries something similar too. So if your in the US you should be ok.


CrazyBillyBob

Thanks, I think we will have to go with something similar. A capacitor would be to much trouble and (in my mind) a bit dangerous for something such as this. I say that because, it will be on all the time, even with the computer off.

+rep

Thanks

[Dilphat]

wow. ok thanks. I might have misunderstood reading it at homedepot or something. haha. i got off of work and checked it. well I'll check again. thanks billybob and dan
+rep