i need a 240v dc power supply for a project but my pablum is ,i need to reduce the current up to 2 amps i know how to reduce the voltage but how i can reduce current ?
to sort of throttle the mains power, and give you AC with less RMS voltage before the rectifier stage.
Regarding cost, cheapness, if you have ever gone shopping for a power supply, you might have noticed price tends to scale with power capacity. So that a little 5W thing to charge your phone is really cheap, and a 30 W brick for charging a laptop is maybe moderately priced.
When I multiply the two numbers in your spec together, I get 480 W, and that is kind of a big number. So there might be some sticker shock, if you actually go shopping for, and find offer for, a professionally made 240VDC, constant voltage, with 2A max current, power supply.
Once got my hand frozen to an arcade gun game after swimming my feet were bare and wet. This occurred at a girls basement with a dangerous faulty un-grounded limited motion metal pistol target game.
The current froze my muscles to the grip and I could not even call for help..
Eventually I was able to release my left leg enough to fall down which pulled my hand loose from the current source.. I was an EE at the time and twice warned the family of the lethal game !
The girls father was totally unconcerned of the danger in his home and I later stopped dating her.. No idea what ever they did about my warning..
Discussions
2 years ago
Can you tell us WHY it needs to be current limited to 2 amps.
In general items draw the current they need. If your wanting a safety limit put a 2 amp fuse in line with the supply.
Answer 2 years ago
current limiting circuits
https://www.google.co.uk/search?q=current+limiting...
2 years ago
Perhaps mains power, plus a simple rectifier circuit, half wave, or full wave, etc:
https://en.wikipedia.org/wiki/Rectifier#Rectifier_...
Then put that in series with one or two incandescent light bulbs,
https://en.wikipedia.org/wiki/Incandescent_light_b...
for to effect your current limiting.
I mean, what I have described is the, uh, "cheap and dirty" way to do this.
Actually, for not much more cost, you could throw in a TRIAC based lamp dimmer,
https://en.wikipedia.org/wiki/Dimmer#Solid-state_d...
to sort of throttle the mains power, and give you AC with less RMS voltage before the rectifier stage.
Regarding cost, cheapness, if you have ever gone shopping for a power supply, you might have noticed price tends to scale with power capacity. So that a little 5W thing to charge your phone is really cheap, and a 30 W brick for charging a laptop is maybe moderately priced.
When I multiply the two numbers in your spec together, I get 480 W, and that is kind of a big number. So there might be some sticker shock, if you actually go shopping for, and find offer for, a professionally made 240VDC, constant voltage, with 2A max current, power supply.
Answer 2 years ago
+1
Excellent answer...
Vina should realize a current limit operates by lowering the voltage when you start to draw over 2 amperes...
Answer 2 years ago
Be aware though that at these levels DC will be deadly to the touch....
Answer 2 years ago
I have twice survived 240 VAC across my chest..
Once got my hand frozen to an arcade gun game after swimming my feet were bare and wet. This occurred at a girls basement with a dangerous faulty un-grounded limited motion metal pistol target game.
The current froze my muscles to the grip and I could not even call for help..
Eventually I was able to release my left leg enough to fall down which pulled my hand loose from the current source.. I was an EE at the time and twice warned the family of the lethal game !
The girls father was totally unconcerned of the danger in his home and I later stopped dating her.. No idea what ever they did about my warning..