Hello, I want to buy a cheap boost converter but NOT that one that amplifies voltage (like 5V to 30V) but something that amplifies the current. From 12V 0.02A I want 5V 5A or something that can boost 1A to 5A. From my 5V 1A phone charger I want to amplify to 5A (the voltage does not matter).
Please, if you know something that covers my requirements send me the link;
Max. price I can pay: $15
No converter can increase the power, which is the product of voltage and current.
You need to be more specific about your requirements, "the voltage does not matter" is unlikely
to be true!
In other words tell us what you are trying to do, let us consider the ways it could be done, otherwise
we'll be in xyproblem territory...
I don't hold out hope of finding an existing commercial device converting 5V 1A to <1V 5A, since it would have
almost no uses.
You could use a rechargeable battery as the "boosted" (5A) current source. Use a battery of suitable Ah rating to provide the current required for the duration of use, then supply the battery from a wallwart charger of a much lower rated output (1A or less).
Alternatively, if you can only supply 1A and you want 5A then you need an SMPS rated at say 30V-to-5V and 5A output. This will demand around 1A input current with a supply of say 30V and will output 5A at 5V (accounting for <100% efficiency)
But, as has been stated, if you want truly constructive answers, you really need to provide information as to what you are trying to achieve.
I have NiCr wire which heats over 1000C* when the current is 5A so thats what I need.
JMD1:
I have NiCr wire which heats over 1000C* when the current is 5A so thats what I need.
So what is the voltage across this wire when it is drawing 5A ? It is this that defines your basic requirement.
Or, to put it another way, do you wish to heat 1cm, 10cm or 1M of wire. Do you know the resistance of your required length at 1000oC. From that resistance value you can calculate the required voltage and hence better define what you are looking for. You will heat 'nothing' with a phone charger.
Note that you cant measure the resistance of the cold wire without correcting for the temperature-dependence of conductivity. I would make the heater wire do what you want with whatever supply you're using now, and measure the voltage across it under those conditions, and go from there.
JMD1:
I have NiCr wire which heats over 1000C* when the current is 5A so thats what I need.
Are you actually expecting any meaningful answers ?
You have not revealed the type of NiCr wire; how thick, how long or any of its characteristics at all.
Neither have you explaine why exactly you want to do this from a mobile phone charger.
Did you try Google ?
I found this in about 10 seconds of searching, it appears to have the information you need;
JMD1:
Okay, this starts to be annoying.
@srnet - 26 gauge and I want to heat about 10cm, also I don't have any power supply different from 9V batteries and phone charger.@stowite - How am I supposed to calculate the resistivity and the voltage???
Using the table found by 'srnet' you will need about 4.1 volts at 3.8 amps (do the calculation yourself to get better accuracy). You will not get this power either from a 9V PP6 battery nor from a standard phone charger no matter how you 'boost' it.
P.S. I don't understand why you find it annoying! We needed the "26 gauge and I want to heat about 10cm" information as well as the 1000 deg C. You provided no useful information until pressed and then took 5 days to post it !
@stowite;
Just for grins I ran the numbers per the charts and it looks like you might have been figuring for 1000 deg F instead of the OP's 1000 deg C. The numbers I came up with are 6.7 Volts and just under 6.9 Amps. That's approaching 50 Watts, or ten times what a cell phone charger can provide, not to mention what is available from smoke detector batteries.
Yes - it never occurred to me that in this day and age people would still use F but then I live on the east side of the pond ! I should have guessed at F since the table used feet and not meters. Your calculations just accentuate the problem.
JMD1:
Okay, this starts to be annoying.
You're annoyed? You're the one making us pry your true requirements out of your fingers. You said you "don't care about voltage", then reveal that it's a heating project, one of the most power-hungry types of load there is.
We're volunteers. We do this because it's our hobby, not our job. "You get what you pay for."
You can boost current at the expense of voltage with a buck converter, or you can boost voltage at the expense of current with a boost converter. That's it. There's nothing you can do to boost power.
Just to give you an idea of the kind of power that heating requires, I have a dumb USB load that's just a pair of large resistors. Each of those resistors (which are in parallel) draws 1 A of current from a USB supply. Together that's 10W. It can take twice as much as your phone charger can supply.
With that amount of power going through them, they get up to a surface temperature of 150 OC. Hot enough to boil water if I spray it on, but nowhere close to the temperature you desire. Pushing them up to 1,000 would require substantially more power than a phone charger can provide, as the posters above me have already calculated.