From: dxmm@albury.nospam.net.au   
      
   On 16/04/14 22:23, Uncle Peter wrote:   
   > On Wed, 16 Apr 2014 13:01:00 +0100, Daniel    
   > wrote:   
   >   
   >> On 16/04/14 06:11, Uncle Peter wrote:   
   >>> How easy would it be for me to change the current rating of a constant   
   >>> current supply?  One from a CREE LED light fitting, which I think is   
   >>> very roughly 0.5 amps at 7V.  I want to lower the current, the voltage   
   >>> is ok.   
   >>>   
   >> My memory of teaching Power Supplies (about 15 years ago), the constant   
   >> current was maintained but keeping the voltage developed across a   
   >> particular resistor constant, so, in theory, by increasing the value of   
   >> the resistor, a lower current would develop the same voltage across the   
   >> sensing resistor.   
   >>   
   >> However, you would have to determine which resistor and which value   
   >> .....!   
   >   
   > Thanks for the tip, I'll run it on a bench with a dummy load and test   
   > some resistor voltages, then try changing one a little.   
      
   If you've got a circuit diagram of your power supply, and you can   
   determine which resister is the "sensing" resister, replace it (for the   
   time being) with a variable resistor/rheostat in the same ohmic range as   
   the sensing resistor until you can determine what value resistor you   
   want to stick in.   
      
   Daniel   
      
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