LED''s In Series.....
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Posts: 46,084
Thank you Nick. Would you expound on why the circuit of four LED's only
needs a total of 20mA when each LED requires 20mA to be at full brightness?
This just isn't making complete sense to me yet and I'm not sure what I'm
missing.
Thanks,
Tim
Original Message
From: Nicholas Judson <judson@f...>
To: Basic Stamp List <basicstamps@yahoogroups.com>
Date: Sunday, April 15, 2001 4:35 PM
Subject: Re: [noparse][[/noparse]basicstamps] LED's In Series.....
>20 mA -- use the 120 Ohm resistor.
>
>for LEDs in parallel, the current is summed.
>
>
>Nick
>
>On Sun, 15 Apr 2001, Tim and Jo wrote:
>
>> I have a question about wiring LED's in series. LED Requirements:
>> Voltage Drop of 2.4V at 20mA. Supply Voltage: 12VDC. I'd like to put
four
>> in series using just one current limiting resistor. I understand that I
>> should add-up the total voltage drop for the four in series, but my
question
>> is, should I divide this by 20mA or by 80mA to calculate the resistor
value?
>> In other words should the series be allowed 20mA total or should I figure
>> 20mA for each LED?
>>
>> 2.4V x 4LED's = 9.6V Total Voltage Drop.
>>
>> 12V - 9.6V = 2.4V Remaining.
>>
>>
>> 2.4V / 20mA = 120 Ohm Resistor?
>> OR
>> 2.4V / 80mA = 30 Ohm Resistor?
>
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
needs a total of 20mA when each LED requires 20mA to be at full brightness?
This just isn't making complete sense to me yet and I'm not sure what I'm
missing.
Thanks,
Tim
Original Message
From: Nicholas Judson <judson@f...>
To: Basic Stamp List <basicstamps@yahoogroups.com>
Date: Sunday, April 15, 2001 4:35 PM
Subject: Re: [noparse][[/noparse]basicstamps] LED's In Series.....
>20 mA -- use the 120 Ohm resistor.
>
>for LEDs in parallel, the current is summed.
>
>
>Nick
>
>On Sun, 15 Apr 2001, Tim and Jo wrote:
>
>> I have a question about wiring LED's in series. LED Requirements:
>> Voltage Drop of 2.4V at 20mA. Supply Voltage: 12VDC. I'd like to put
four
>> in series using just one current limiting resistor. I understand that I
>> should add-up the total voltage drop for the four in series, but my
question
>> is, should I divide this by 20mA or by 80mA to calculate the resistor
value?
>> In other words should the series be allowed 20mA total or should I figure
>> 20mA for each LED?
>>
>> 2.4V x 4LED's = 9.6V Total Voltage Drop.
>>
>> 12V - 9.6V = 2.4V Remaining.
>>
>>
>> 2.4V / 20mA = 120 Ohm Resistor?
>> OR
>> 2.4V / 80mA = 30 Ohm Resistor?
>
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>