Re: LED Backlight Tester model A : The world first battery TV led tester
I bet if you measure the current when using your tester with 1 LED an when with one big LED string I am sure the current will not be the same and that is problem with simple Voltage supply instead of constant current power supply, and if the string has shorted LED's the you cannot really calculate how many there are in the string.
BTW, what do you mean "yes, its light was very dim. 84*3.3=277.6v and 184v These two have great differences!" You actually measure Vf of 277.6V on the good LED string? 184V at how many mA? I have a feeling that you are driving the LED striking at a lot less than 30mA, power at 184V @30mA = 5.5 Watts! Guess how much current you will be drawing from 1.5V power supply? Does your power supply really has that much power? You need to monitor the LED current.
I bet if you measure the current when using your tester with 1 LED an when with one big LED string I am sure the current will not be the same and that is problem with simple Voltage supply instead of constant current power supply, and if the string has shorted LED's the you cannot really calculate how many there are in the string.
BTW, what do you mean "yes, its light was very dim. 84*3.3=277.6v and 184v These two have great differences!" You actually measure Vf of 277.6V on the good LED string? 184V at how many mA? I have a feeling that you are driving the LED striking at a lot less than 30mA, power at 184V @30mA = 5.5 Watts! Guess how much current you will be drawing from 1.5V power supply? Does your power supply really has that much power? You need to monitor the LED current.
Comment