Register to reply

Converting 24v to 12v

by elevfan7072
Tags: converting
Share this thread:
elevfan7072
#1
Nov8-12, 02:08 PM
P: 4
I recently found a 24v scooter on Craigslist. I would look forward to wiring a horn to it. I don't know what kind of resistor I should use.
Phys.Org News Partner Engineering news on Phys.org
Tricorder XPRIZE: 10 teams advance in global competition to develop consumer-focused diagnostic device
Study shows local seismic isolation and damping methods provide optimal protection for essential computing equipment
New filter technology uses inert gas to bore holes in high-quality steel
sophiecentaur
#2
Nov8-12, 04:46 PM
Sci Advisor
Thanks
PF Gold
sophiecentaur's Avatar
P: 12,170
Wire two identical 12V horns in series. That is the easiest solution. Alternatively, you are going to need to waste power in a dropper resistor and you would need to work out its value. Two horns in series will produce twice as much noise and waste no power. Plus, you won't need to do any sums!
davenn
#3
Nov8-12, 07:24 PM
Sci Advisor
PF Gold
davenn's Avatar
P: 2,647
And the other obvious alternative is ....

there are plenty of 24V horns available for trucks etc
take a trip to your local vehicle wreckers and look through the recovered parts.
many wreckers let you look through vehicles yourself and recover the part you need ... take it to the counter and pay for it

Dave

elevfan7072
#4
Nov28-12, 12:12 PM
P: 4
Converting 24v to 12v

Oh Or if I only use one I could just use a 7812!
berkeman
#5
Nov28-12, 01:01 PM
Mentor
berkeman's Avatar
P: 41,085
Quote Quote by elevfan7072 View Post
Oh Or if I only use one I could just use a 7812!
You certainly could, but you will need to figure out the horn current and then how much power that means when you drop 12V across the 7812. Luckily the horn will only be used intermittantly, so it may not take much heat sinking of the 7812 to make it work.

A better solution is to use a DC-DC converter (buck topology) to drop the voltage with little power dissipation. The Simple Switcher series of DC-DC converters from National Instruments is a good place to start if you want to try that route...
davenn
#6
Nov28-12, 01:34 PM
Sci Advisor
PF Gold
davenn's Avatar
P: 2,647
you will probably find that the current requird by one 12V vehicle type horn well exceeds the 1A capability of a 7812 regulator chip.

Dave


Register to reply

Related Discussions
Converting ppm to mg/L Biology, Chemistry & Other Homework 3
Converting m/s/s to g's Introductory Physics Homework 2
Converting AC to DC Electrical Engineering 8
Converting mph Introductory Physics Homework 6
I need help converting kg/s! Introductory Physics Homework 4