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#1
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LED's in series
I have used LED's many times before but never in series.
I need to run as many LED's as possible from a 12v supply. Is there a formula for series LED connections ? All advise welcome. Norman |
#2
Posted to alt.electronics
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LED's in series
"Norman" wrote in message o.uk... I have used LED's many times before but never in series. I need to run as many LED's as possible from a 12v supply. Is there a formula for series LED connections ? Multiply the drop across one LED by the number in series (e.g., 2 V x 6 = 12 V) up to the limit of the supply. However, it is better to leave a couple of volts for a series resistor. So, you could connect 5 in series with a 100 ohm resistor. Even better, use a constant current supply with a compliance voltage range large enough to forward bias all of the diodes. |
#3
Posted to alt.electronics
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LED's in series
"Charles" wrote in message ... "Norman" wrote in message o.uk... I have used LED's many times before but never in series. I need to run as many LED's as possible from a 12v supply. Is there a formula for series LED connections ? Multiply the drop across one LED by the number in series (e.g., 2 V x 6 = 12 V) up to the limit of the supply. However, it is better to leave a couple of volts for a series resistor. So, you could connect 5 in series with a 100 ohm resistor. Even better, use a constant current supply with a compliance voltage range large enough to forward bias all of the diodes. Cheers for the help. I have not been ignoring you, my PC decided to clean up my news massages and I cant get them back. Reading your suggestion I am guessing that the 100 ohm resistor is enough to lose 2 volts. eg. if my final voltage is 14 volts, I can get away with 6 leds and a 100 ohm res ? Also guessing I needs to know if the leds want 2v or 1.6 / 1.8v ? |
#4
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LED's in series
On Wed, 18 Jul 2007 17:20:33 +0100, "Norman"
wrote: "Charles" wrote in message ... "Norman" wrote in message o.uk... I have used LED's many times before but never in series. I need to run as many LED's as possible from a 12v supply. Is there a formula for series LED connections ? Multiply the drop across one LED by the number in series (e.g., 2 V x 6 = 12 V) up to the limit of the supply. However, it is better to leave a couple of volts for a series resistor. So, you could connect 5 in series with a 100 ohm resistor. Even better, use a constant current supply with a compliance voltage range large enough to forward bias all of the diodes. Cheers for the help. I have not been ignoring you, my PC decided to clean up my news massages and I cant get them back. Reading your suggestion I am guessing that the 100 ohm resistor is enough to lose 2 volts. eg. if my final voltage is 14 volts, I can get away with 6 leds and a 100 ohm res ? Also guessing I needs to know if the leds want 2v or 1.6 / 1.8v ? Short of looking at the specifications for your particular LED, let's say 1.6 volts. Feeding 14 volts would require (guesstimate) about 200 ohms. |
#5
Posted to alt.electronics
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LED's in series
http://en.wikipedia.org/wiki/LED_circuit
"PeterD" wrote in message ... On Wed, 18 Jul 2007 17:20:33 +0100, "Norman" wrote: "Charles" wrote in message ... "Norman" wrote in message o.uk... I have used LED's many times before but never in series. I need to run as many LED's as possible from a 12v supply. Is there a formula for series LED connections ? Multiply the drop across one LED by the number in series (e.g., 2 V x 6 = 12 V) up to the limit of the supply. However, it is better to leave a couple of volts for a series resistor. So, you could connect 5 in series with a 100 ohm resistor. Even better, use a constant current supply with a compliance voltage range large enough to forward bias all of the diodes. Cheers for the help. I have not been ignoring you, my PC decided to clean up my news massages and I cant get them back. Reading your suggestion I am guessing that the 100 ohm resistor is enough to lose 2 volts. eg. if my final voltage is 14 volts, I can get away with 6 leds and a 100 ohm res ? Also guessing I needs to know if the leds want 2v or 1.6 / 1.8v ? Short of looking at the specifications for your particular LED, let's say 1.6 volts. Feeding 14 volts would require (guesstimate) about 200 ohms. |
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