Green LED on RPI 3B+ GPIO
I have seen a few examples of wiring a red LED directly from the RPI GPIO pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma,
so if I use the 5V power on pin 1 would I end up with
5V - 3.3V = 1.7.
1.7 V = 20 mA × R
or rephrased:
1.7 V / 20 mA = R
and when we solve that we get:
1.7 V / 20 mA = 1.7 V / 0.020 A = 85Ω ?
gpio pi-3b+
edited Dec 15 at 11:07
Ghanima♦
11.9k93975
asked Dec 9 at 17:33
Mortifis
111
add a comment |
I have seen a few examples of wiring a red LED directly from the RPI GPIO pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma,
so if I use the 5V power on pin 1 would I end up with
5V - 3.3V = 1.7.
1.7 V = 20 mA × R
or rephrased:
1.7 V / 20 mA = R
and when we solve that we get:
1.7 V / 20 mA = 1.7 V / 0.020 A = 85Ω ?
gpio pi-3b+
edited Dec 15 at 11:07
Ghanima♦
11.9k93975
asked Dec 9 at 17:33
Mortifis
111
There are two common chemistries used when making green LEDs. The traditional gives a warmer green and is more related to the red, yellow and orange and requires roughly 2 volts to operate. The green used in an RGB LED is typically colder in order to improve the gamut, and has a higher voltage, but are also available as discrete LEDs. You should figure out which one you have.
– pipe
Dec 9 at 22:48
add a comment |
I have seen a few examples of wiring a red LED directly from the RPI GPIO pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma,
so if I use the 5V power on pin 1 would I end up with
5V - 3.3V = 1.7.
1.7 V = 20 mA × R
or rephrased:
1.7 V / 20 mA = R
and when we solve that we get:
1.7 V / 20 mA = 1.7 V / 0.020 A = 85Ω ?
gpio pi-3b+
edited Dec 15 at 11:07
Ghanima♦
11.9k93975
asked Dec 9 at 17:33
Mortifis
111
I have seen a few examples of wiring a red LED directly from the RPI GPIO pins, however, I need to wire a GREEN LED and am having trouble calculating the resistor needed. I believe that a green LED uses 3.3 volts and at 20ma,
so if I use the 5V power on pin 1 would I end up with
5V - 3.3V = 1.7.
1.7 V = 20 mA × R
or rephrased:
1.7 V / 20 mA = R
and when we solve that we get:
1.7 V / 20 mA = 1.7 V / 0.020 A = 85Ω ?
gpio pi-3b+
gpio pi-3b+
edited Dec 15 at 11:07
Ghanima♦
11.9k93975
asked Dec 9 at 17:33
Mortifis
111
edited Dec 15 at 11:07
Ghanima♦
11.9k93975
asked Dec 9 at 17:33
Mortifis
111
edited Dec 15 at 11:07
Ghanima♦
11.9k93975
edited Dec 15 at 11:07
Ghanima♦
11.9k93975
edited Dec 15 at 11:07
Ghanima♦
11.9k93975
11.9k93975
asked Dec 9 at 17:33
Mortifis
111
asked Dec 9 at 17:33
Mortifis
111
asked Dec 9 at 17:33
Mortifis
111
111
There are two common chemistries used when making green LEDs. The traditional gives a warmer green and is more related to the red, yellow and orange and requires roughly 2 volts to operate. The green used in an RGB LED is typically colder in order to improve the gamut, and has a higher voltage, but are also available as discrete LEDs. You should figure out which one you have.
– pipe
Dec 9 at 22:48
add a comment |
There are two common chemistries used when making green LEDs. The traditional gives a warmer green and is more related to the red, yellow and orange and requires roughly 2 volts to operate. The green used in an RGB LED is typically colder in order to improve the gamut, and has a higher voltage, but are also available as discrete LEDs. You should figure out which one you have.
– pipe
Dec 9 at 22:48
There are two common chemistries used when making green LEDs. The traditional gives a warmer green and is more related to the red, yellow and orange and requires roughly 2 volts to operate. The green used in an RGB LED is typically colder in order to improve the gamut, and has a higher voltage, but are also available as discrete LEDs. You should figure out which one you have.
– pipe
Dec 9 at 22:48
There are two common chemistries used when making green LEDs. The traditional gives a warmer green and is more related to the red, yellow and orange and requires roughly 2 volts to operate. The green used in an RGB LED is typically colder in order to improve the gamut, and has a higher voltage, but are also available as discrete LEDs. You should figure out which one you have.
– pipe
Dec 9 at 22:48
add a comment |
1 Answer
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I have powered green, red, yellow, and multi-colored LEDs direct from the (3V3) GPIO. So a green LED forward voltage of 3V3 seems unlikely.
Anyhow putting 20mA through a modern LED would be absurdly bright.
Try something in the range 300-500 ohms (or higher) and use PWM on the GPIO to vary the brightness if needed.
answered Dec 9 at 17:45
joan
48.9k34881
add a comment |
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I have powered green, red, yellow, and multi-colored LEDs direct from the (3V3) GPIO. So a green LED forward voltage of 3V3 seems unlikely.
Anyhow putting 20mA through a modern LED would be absurdly bright.
Try something in the range 300-500 ohms (or higher) and use PWM on the GPIO to vary the brightness if needed.
answered Dec 9 at 17:45
joan
48.9k34881
add a comment |
I have powered green, red, yellow, and multi-colored LEDs direct from the (3V3) GPIO. So a green LED forward voltage of 3V3 seems unlikely.
Anyhow putting 20mA through a modern LED would be absurdly bright.
Try something in the range 300-500 ohms (or higher) and use PWM on the GPIO to vary the brightness if needed.
answered Dec 9 at 17:45
joan
48.9k34881
add a comment |
I have powered green, red, yellow, and multi-colored LEDs direct from the (3V3) GPIO. So a green LED forward voltage of 3V3 seems unlikely.
Anyhow putting 20mA through a modern LED would be absurdly bright.
Try something in the range 300-500 ohms (or higher) and use PWM on the GPIO to vary the brightness if needed.
answered Dec 9 at 17:45
joan
48.9k34881
I have powered green, red, yellow, and multi-colored LEDs direct from the (3V3) GPIO. So a green LED forward voltage of 3V3 seems unlikely.
Anyhow putting 20mA through a modern LED would be absurdly bright.
Try something in the range 300-500 ohms (or higher) and use PWM on the GPIO to vary the brightness if needed.
answered Dec 9 at 17:45
joan
48.9k34881
answered Dec 9 at 17:45
joan
48.9k34881
answered Dec 9 at 17:45
joan
48.9k34881
answered Dec 9 at 17:45
joan
48.9k34881
48.9k34881
add a comment |
add a comment |
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There are two common chemistries used when making green LEDs. The traditional gives a warmer green and is more related to the red, yellow and orange and requires roughly 2 volts to operate. The green used in an RGB LED is typically colder in order to improve the gamut, and has a higher voltage, but are also available as discrete LEDs. You should figure out which one you have.
– pipe
Dec 9 at 22:48