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Is these LED status work ? ( LM317 Contant Current Charger )

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tong

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Is these LED status work ? :oops:
Voltage across is 1.8v to 2.1v
 

kgl_13gr

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depends on you resistor value. usually the LEDs need some amount of current to flow through in order to work
 

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LAKMON

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Re: Is these LED status work ? ( LM317 Contant Current Charg

What values are Two resistor in circuit ? and Source voltage ?
 

flatulent

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Re: Is these LED status work ? ( LM317 Contant Current Charg

If the constant current is within the LED rating you do not need the diodes and resistor. Why do you need the LED? With the constant current, it will only indicate that there is a battery connected.

A cheaper way is to first calculate the voltage across the LED when it is lit. Usually 10 mA is a good current for them. Then calculate the resistor value as the LED voltage divided by the constant current minus 10 mA.

You can also use incandescent light bulbs. They will glow red with less than rated current and last longer.
 

tong

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Yes, I want it indicate that there is a battery connected.


charging current 0.6A, The first R is 1 ohm.


3 diodes make a voltage drop and bypass 590mA.


R Led = 10 ohm = ( 2.1 - 2 ) / 0.010


Is these work ?
 

barrybear

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Re: Is these LED status work ? ( LM317 Contant Current Charg

Make sure that the 3 diodes are capable of taking the charge current for the battery. Use IN4001 for currents up to 900ma.

Barrybear
 

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