Output 12-30V with 20mA Electrical Source

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nikayout

Joined Apr 13, 2017
7
Hello, i need 12-30V with 20mA output for my project, can anyone tell me how to get this ?
i have found dc electrical sources which gives 500mA but it is too much. i need 20mA.
 

OBW0549

Joined Mar 2, 2015
3,566
The 500 mA ratings on the DC sources you looked at only express how much current the sources can supply (without overheating or shutting down); the actual current supplied will be only what your project draws. So, while a 500 mA source is certainly more than you need for the job, it absolutely will NOT force excessive current into your device. In other words, the voltage source determines the voltage; the load determines the current at that voltage.
 

ericgibbs

Joined Jan 29, 2010
11,108
hi nika,
Your project will only draw the 20mA it needs from the 500mA source.

What is the voltage source and details of your project.

E
 

Thread Starter

nikayout

Joined Apr 13, 2017
7
The 500 mA ratings on the DC sources you looked at only express how much current the sources can supply (without overheating or shutting down); the actual current supplied will be only what your project draws. So, while a 500 mA source is certainly more than you need for the job, it absolutely will NOT force excessive current into your device.
i do not know anything about electronics
i need this device for iontophoresis
i have searched information about this rayovac latern battery 12V amperage and found nothing.
20mA + is dangerous for me, is it possible to get exactly 20mA with 12-30V ?
 

Thread Starter

nikayout

Joined Apr 13, 2017
7
Wow it is amazing but there is one another problem my dc source have max 12V and i need this all
other project do not Misappropriation my V 's ?
 

OBW0549

Joined Mar 2, 2015
3,566
i do not know anything about electronics
i need this device for iontophoresis
20mA + is dangerous for me, is it possible to get exactly 20mA with 12-30V ?
If you truly don't know anything about electronics (and your comments indicate you don't), then you absolutely SHOULD NOT be fooling around with iontophoresis. This stuff is not for amateurs, and especially not for beginning amateurs; leave it to the professionals.
 

AlbertHall

Joined Jun 4, 2014
10,551
You should use a battery (or batteries) for this on safety grounds. You are connecting your body to the electrical power and if you use a mains powered supply you are at risk should that supply develop a fault. Any battery, or combination of batteries, supplying the correct voltage will do the job.

Incidentally, it is also important that the two bowls do not touch each other and they are very, very close in the video. If they touch this will stop the treatment and quickly discharge the battery.
 

Thread Starter

nikayout

Joined Apr 13, 2017
7
You should use a battery (or batteries) for this on safety grounds. You are connecting your body to the electrical power and if you use a mains powered supply you are at risk should that supply develop a fault. Any battery, or combination of batteries, supplying the correct voltage will do the job.

Incidentally, it is also important that the two bowls do not touch each other and they are very, very close in the video. If they touch this will stop the treatment and quickly discharge the battery.
Thanks for replay AlbertHall, so if i use correct voltage battery it does not matter how much is ampere ?
 

Thread Starter

nikayout

Joined Apr 13, 2017
7
If you truly don't know anything about electronics (and your comments indicate you don't), then you absolutely SHOULD NOT be fooling around with iontophoresis. This stuff is not for amateurs, and especially not for beginning amateurs; leave it to the professionals.
Yes, i am begginer in this subject but i know how much voltage and mA i need
so that i need help from poeple who know this how to get 20mA with 12-30V
 

bertus

Joined Apr 5, 2008
20,876
Hello,

When you want a short circuit current of maximum 20 mA, just put a resistor of 600 Ohms or more in series with the 12 Volts powersupply.
That way the current can never be larger as 20 mA.

Bertus
 

Thread Starter

nikayout

Joined Apr 13, 2017
7
Hello,

Did you read post#12?
There I described how you can limit the current.

Bertus
Hello bertus, i have read your post but i am very begginer and do not know how to do this and now i am trying to find and buy device which is already ready for use.
 

JohnInTX

Joined Jun 26, 2012
4,341
I think you don't want to put your hands into saltwater that is energized by some garden-variety mains-connected power supply, especially one of unknown pedigree. Medical-grade supplies are expensive for a reason, they provide a very high degree of isolation from mains. Some cheapo supplies do not and that can kill you. Some battery types can explode or cause fires if shorted (like your two pans touching).

If you must proceed with this, use the battery shown and current limit it like @bertus suggests.

Based on the inherent and potential hazards this thread will be closed.
 
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