DC Adapter Voltage & MA Basic Info, Please - Electrical - DIY Chatroom Home Improvement Forum


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Display Modes
Old 03-18-2012, 09:53 PM   #1
Newbie
 
Join Date: Mar 2012
Posts: 3
Rewards Points: 10
Default

DC adapter Voltage & mA basic info, please


Hello, I have a desktop nightlight for my little girl that requires a "4.5V 50mA" DC adapter. I have found one in our "junk drawer" that is 4.5V, but says 250mA. Can I use that one, or will the extra 200mA damage the unit?
(I know nothing of electrical matters.) Thank you for whoever takes the time to respond. I appreciate it.

Advertisement

buyerpro is offline   Reply With Quote
Old 03-18-2012, 10:03 PM   #2
Member
 
Join Date: Nov 2011
Location: Md/Pa
Posts: 1,511
Rewards Points: 1,378
Default

DC adapter Voltage & mA basic info, please


It should be fine. You can go larger on the amps but not smaller.

Advertisement

zappa is online now   Reply With Quote
The Following User Says Thank You to zappa For This Useful Post:
buyerpro (03-18-2012)
Old 03-18-2012, 10:08 PM   #3
Newbie
 
Join Date: Mar 2012
Posts: 3
Rewards Points: 10
Default

DC adapter Voltage & mA basic info, please


Thank you, Zappa, and what is the difference btwn "Voltage" and "amps" then? In layman's terms? Tracie
buyerpro is offline   Reply With Quote
Old 03-18-2012, 10:17 PM   #4
Member
 
Join Date: Nov 2011
Location: Md/Pa
Posts: 1,511
Rewards Points: 1,378
Default

DC adapter Voltage & mA basic info, please


Quote:
Originally Posted by buyerpro View Post
Thank you, Zappa, and what is the difference btwn "Voltage" and "amps" then? In layman's terms? Tracie
Ummmmm....voltage would be like the water pressure in a garden hose and amps would be the flow, or gallons per minute.

Maybe someone else can come up with something easier to understand but I can't think of anything off the top of me head. An internet search could help also.
zappa is online now   Reply With Quote
Old 03-18-2012, 10:30 PM   #5
Member
 
Join Date: Nov 2011
Location: Md/Pa
Posts: 1,511
Rewards Points: 1,378
Default

DC adapter Voltage & mA basic info, please


In your case you don't want to go higher or lower with the volts because that is what the lamp wants to see or is rated for. It will only draw 50ma and the larger power supply will only deliver what the lamp is calling for and will be like in retirement mode just putzing along and very happy not having to work very hard.
zappa is online now   Reply With Quote
Old 03-18-2012, 10:35 PM   #6
Newbie
 
Join Date: Mar 2012
Posts: 3
Rewards Points: 10
Default

DC adapter Voltage & mA basic info, please


Thanks so much for kindly taking your time to answer me, Zappa. In looking further, I have found that apparently I need to be very careful about "polarity." I know I can look on the appliance and see that it may say "DC", but how do I know if I have the polarity correct? I'm not really understanding what this final step is. Can you help? What notations am I looking for on both the adapter & the appliance to know if the adapter is compatible with the appliance in terms of polarity? Thanks again!
buyerpro is offline   Reply With Quote
Old 03-18-2012, 10:40 PM   #7
Member
 
Join Date: Nov 2011
Location: Md/Pa
Posts: 1,511
Rewards Points: 1,378
Default

DC adapter Voltage & mA basic info, please


There should be a black dot with an open circle around the black dot if you have the round popular connector I'm thinking of. There will be + and - pointing to the black dot and open circle. If both the power supply and the lamp match you should be good to go.

There are also a few different sizes (diameters) of connectors so that may be another problem if they don't match.

Last edited by zappa; 03-19-2012 at 06:42 AM.
zappa is online now   Reply With Quote
Old 03-18-2012, 11:09 PM   #8
Member
 
Join Date: Oct 2010
Location: Cairns Australia
Posts: 2,721
Rewards Points: 2,402
Default

DC adapter Voltage & mA basic info, please


Quote:
Originally Posted by buyerpro View Post
Thanks so much for kindly taking your time to answer me, Zappa. In looking further, I have found that apparently I need to be very careful about "polarity." I know I can look on the appliance and see that it may say "DC", but how do I know if I have the polarity correct? I'm not really understanding what this final step is. Can you help? What notations am I looking for on both the adapter & the appliance to know if the adapter is compatible with the appliance in terms of polarity? Thanks again!
Most things will have an polarity mark on them.
And also most power adaptors have a mark on them.
So it is good to look closely at each to be sure.

The most common is tip is positive.

Advertisement

dmxtothemax is online now   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Voltage Problem H. Bruce Electrical 5 09-24-2010 01:14 PM
Reduced Voltage Supply to Outdoor Light mark2741 Electrical 6 09-05-2010 03:44 PM
DC voltage from a PCB dave11 Electrical 3 07-20-2010 07:13 PM
Need basic breaker info please honker Electrical 176 06-01-2008 11:10 AM
Need info on Basic Member Sizing etc. exup Building & Construction 3 01-18-2008 05:47 PM




Top of Page | View New Posts