where can i find a dc transformer??
- Thread starter Bushman
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ElektroLumens
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Bushman:
so on your home brew set up do you have a display that allows you to tell how many mA's and volts you are driving said led/array?<HR></BLOCKQUOTE>
Bushman,
Yes, I do. I have a digital voltmeter, which tells me the voltage. I also use a .1 ohm resistor, and use it in series with the circuit I'm driving, and I measure the voltage across the resistor. This tells me the current the circuit is using. There are a few posts here on the CPF explaining how to do this. If you try to measure such small current with the DVM, it will not be very accurate.
Wayne
so on your home brew set up do you have a display that allows you to tell how many mA's and volts you are driving said led/array?<HR></BLOCKQUOTE>
Bushman,
Yes, I do. I have a digital voltmeter, which tells me the voltage. I also use a .1 ohm resistor, and use it in series with the circuit I'm driving, and I measure the voltage across the resistor. This tells me the current the circuit is using. There are a few posts here on the CPF explaining how to do this. If you try to measure such small current with the DVM, it will not be very accurate.
Wayne
i would like to get a transformer for testing led arrays (and individual led's) probably needs to run from 1.5 to 12 volts and adjustable current from 10 mA to 500 mA any ideas on where to get such a beast? or is there even such a beast to be had?
ElektroLumens
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Bushman:
i would like to get a transformer for testing led arrays (and individual led's) probably needs to run from 1.5 to 12 volts and adjustable current from 10 mA to 500 mA any ideas on where to get such a beast? or is there even such a beast to be had?<HR></BLOCKQUOTE>
I assume you're referring to an AC/DC transformer. I use an ordinary 12 volt wall power supply. I connect this to a DC/DC regulator I designed and put together using a LM317 chip, which is super common and cheap. I can vary the output voltage from 1 volt to around 12 volts,and it can supply up to 1 amp. You can purchase kits for this common lossy step down regulator. It is not good for using with batteries because it is very inefficient, but works quite well with a wall transformer, for testing purposes.
You can also purchase a bench power supply, which for a variable supply like you are asking about, would cost probably between $70 - $100, or much more, depending upon the amperage you need.
i would like to get a transformer for testing led arrays (and individual led's) probably needs to run from 1.5 to 12 volts and adjustable current from 10 mA to 500 mA any ideas on where to get such a beast? or is there even such a beast to be had?<HR></BLOCKQUOTE>
I assume you're referring to an AC/DC transformer. I use an ordinary 12 volt wall power supply. I connect this to a DC/DC regulator I designed and put together using a LM317 chip, which is super common and cheap. I can vary the output voltage from 1 volt to around 12 volts,and it can supply up to 1 amp. You can purchase kits for this common lossy step down regulator. It is not good for using with batteries because it is very inefficient, but works quite well with a wall transformer, for testing purposes.
You can also purchase a bench power supply, which for a variable supply like you are asking about, would cost probably between $70 - $100, or much more, depending upon the amperage you need.
