laser lights

[ECET0purdue]

hello,

ok i got an 24v power supply going to a POT. i then get 5V from the POT.
the POT is 2 watts 5k.  The laser lights are pulling 65MA and are 5V This will not work?  if i connect it to The pot it, the voltage drop is too much.. now the question is what kind of POT should i get? more or less watts or ohms, and whould it have any effect on the 24Vs comming in...(iam using the 24 volts for another divice) any help would be good thanks.
glen

 

[MP1]

It will be better to use a voltage regulator instead of a pot. Especially when you are powering more than one device at different voltages. The resistance of the pot will become part of ohms law of your other branch of the circuit. Load will shift. In other words, you will never get a steady current as other loads on the circuit are attached or vary. Actually, a LM7805 probably costs less than a 2 watt 5K pot.

MP

 

[ECET0purdue]

would it get to hot going from 24v to 5v and can they handle 65 ma? and ...what Would be the best kind to buy?  and..........just playing..
lol
cheers,
glen

 

[audioguru2]

Hi Glen,
A 5V regulator like a 7805T would have 19V across it and 65mA through it. Therefore it must dissipate 1.2W and would be very hot without a small heatsink. ;D

 

[ECET0purdue]

so better off just using a 5volt power supply...???  unless you know of any other items that might help?????

 

[Cuckoo1]

Hi

You may have already built that 5V supply but... I recently found some ready made very easy to use switching regulators made by Texas Instruments (Powertrends to be more specific). They do operate at 24V, have outputs of 5V, as you need, and adequate output currents. What is even better is that you can have free samples of them. Check out PT5100 (5V/1A) or PT4142 (5V/4A), You may look at TI's site under:
Analog and Mixed signal -> Power management -> Plug-in power modules
and find the regulator that suits you best.