Nā nīnau hoʻohālike e kūkākūkā ana i nā Diodes Hoʻopuka Mālamalama (LED)
ʻO ka diode hoʻomāmā kukui (LED) he mea semiconductor e hoʻopuka i ka mālamalama ke kahe ka uila ma o ia mea. ʻO ka hanana ma hope o nā LED ua kapa ʻia ʻo electroluminescence, kahi e hoʻopuka ai kahi mea semiconductor i ka mālamalama ke hoʻonāukiuki ʻia e ka uila. Ua lilo nā LED i mea kaulana loa i nā ʻano hana like ʻole ma muli o ko lākou pono kiʻekiʻe a me ke ola lōʻihi i hoʻohālikelike ʻia me nā kumu kukui kuʻuna e like me nā kukui incandescent.
Ma kēia ʻatikala, e kūkākūkā mākou i kekahi mau pilikia hoʻohālike e pili ana i nā LED a wehewehe i kā lākou mau hoʻonā a me nā kūkākūkā kikoʻī e kōkua i ka hoʻomaopopo ʻana i ke kumumanaʻo ma hope o kēia hanana.
Laʻana Nīnau 1: Nā Waiwai Kumu o nā LED
Nīnau: Loaʻa i kahi LED ka hiki ke hoʻopuka i ka mālamalama me ka nalu o 650 nm (nanometers). E helu i ka ikehu o nā photons i hoʻopuka ʻia e kēia LED ma nā electron-volts (eV).
Kūkākūkā:
Hiki ke helu ʻia ka ikehu photon me ka hoʻohana ʻana i ka hoʻohālikelike a Planck:
\[ E = \frac{hc}{\lambda} \]
Ma hea:
– ʻO \( E \) ka ikehu photon,
– ʻO \( h \) ke kūpaʻa o Planck (\(6.626 \times 10^{-34} \text{ Js}\)),
– ʻO \( c \) ka wikiwiki o ka mālamalama (\(3 \times 10^8 \text{ m/s}\)),
– ʻO \( \lambda \) ka nalu o ke kukui (650 nm a i ʻole \(650 \times 10^{-9} \text{ m}\)).
ʻO ka hoʻololi ʻana i kēia mau waiwai i loko o ka hoohalike e loaʻa ai:
\[
E = 6.626 manawa 10^{-34 manawa 3 manawa 10^8}{650 manawa 10^{-9}}
= \frac{1.9878 \times 10^{-25}}{650 \times 10^{-9}}
= 3.05 \times 10^{-19} \text{ J}
\]
ʻO ka mea aʻe, hoʻololi mākou i nā Joules i nā electron-volts me ka hoʻohana ʻana i ka hoʻololi \(1 \text{ eV} = 1.602 \times 10^{-19} \text{ J}\):
\[
E = 3.05 manawa 10^{-19}}{1.602 manawa 10^{-19}}
≈ 1.90 \text{ eV}
\]
No laila, ʻo ka ikehu photon i hoʻopuka ʻia e kahi LED me ka nalu lōʻihi o 650 nm ma kahi o 1.90 eV.
Laʻana 2: Ka Uila Hoʻokele LED
Nīnau: He 2V ka volta i mua o kahi LED ʻulaʻula a koi ʻia ke au o 20 mA e hana pono ai. E helu i ka mana i hoʻopau ʻia e ka LED.
Kūkākūkā:
No ka helu ʻana i ka mana i hoʻopili ʻia e ka LED, hoʻohana mākou i ka hoohalike kumu no ka mana, ʻo ia hoʻi:
\[ P = V \times I \]
Ma hea:
– ʻO \( P \) ka mana ma Watts (W),
– ʻO \( V \) ka uila ma Volts (V),
– ʻO \( I \) ke au ma Amperes (A).
E hoʻololi i kēia mau waiwai i loko o ka hoohalike:
\[
P = 2 \text{ V} \times 20 \text{ mA}
= 2 \text{ V} \times 0.02 \text{ A}
= 0.04 \text{ W}
\]
No laila, ʻo ka mana i hoʻopili ʻia e kahi LED ʻulaʻula e hana ana ma kahi volta i mua o 2V a me ke au o 20 mA he 0.04 Watts.
Laʻana 3: Ka pono o ka LED
Nīnau: He 30% ka pono quantum o kahi LED polū. Inā hoʻohana ka LED i 0.1 W o ka mana uila, ehia ka nui o ka mana i hoʻopuka ʻia ma ke ʻano he mālamalama?
Kūkākūkā:
ʻO ka pono Quantum (η) ka lakio o ka mana i hoʻokuʻu ʻia ma ke ʻano o ka mālamalama (P_luminous) i ka mana uila i hoʻokomo ʻia (P_input):
\[ η = \frac{P_{\text{luminous}}}{P_{\text{input}}} \]
No ka loaʻa ʻana o \( P_{\text{luminous}} \), e hoʻohana i ka hoohalike ma lalo nei me ka waiwai pono o 30% a i ʻole 0.30:
\[
0.30 = \frac{P_{\text{luminous}}}{0.1 \text{ W}}
\]
Penei:
\[
P_{\text{luminous}} = 0.30 \times 0.1 \text{ W}
= 0.03 \text{ W}
\]
No laila, ʻo ka mana i hoʻokuʻu ʻia e ka LED ma ke ʻano o ke kukui he 0.03 Watt.
Laʻana Pilikia 4: Kaapuni LED Series
Nīnau: Loaʻa iā ʻoe ʻekolu mau LED me ka volta i mua o 2V kēlā me kēia e pono e hoʻopili ʻia ma ke ʻano he moʻo. Inā ʻo 9V ke kumu volta, e hoʻoholo i ka waiwai o ke kū'ē e pono ai e kaupalena i ke au i 20 mA.
Kūkākūkā:
Ke hoʻopili ʻia nā LED ma ke ʻano series, ʻo ka huina voltage e pono ai ʻo ia ka huina o nā voltage i mua o kēlā me kēia LED:
\[
V_{ka huina} = V_f1 + V_f2 + V_f3
= 2V + 2V + 2V
= 6V
\]
ʻO ke koena voltage e pono e hoʻokahe ʻia e ka resistor:
\[
V_{R} = V_{kumu} – V_{huina}
= 9V – 6V
= 3V
\]
Me kahi au i makemake ʻia o 20 mA, ua helu ʻia ka waiwai resistor me ka hoʻohana ʻana i ke Kānāwai o Ohm:
\[
R = \frac{V_{R}}{I}
= \frac{3V}{20 \text{ mA}}
= \frac{3V}{0.02A}
= 150 \Omega
\]
No laila, ʻo ka waiwai o ke kū'ē i koi ʻia he 150 ohms.
Laʻana 5: Kaapuni Palena o ke Au LED Parallel
Nīnau: I loko o kahi kaapuni, aia ʻelua mau LED i ka ʻaoʻao like, kēlā me kēia me kahi uila i mua o 2V a me ke au o 20 mA. He aha ka huina o ke au e pono ai mai kahi kumu uila 5V inā hoʻohana ʻia kahi resistor no kēlā me kēia LED?
Kūkākūkā:
No nā LED i hoʻonohonoho ʻia ma ke ʻano like, e ʻike kēlā me kēia LED i ka volta like, ʻo ia hoʻi ko lākou volta mua, a no ka mea e pono ai lākou i 20 mA o ke au no kēlā me kēia LED, ʻo ke au holoʻokoʻa:
\[
ʻI_{total} = I_1 + I_2
= 20 \ kikokikona { mA} + 20 \ kikokikona { mA}
= 40 mA
\]
No ka helu ʻana i ka waiwai resistor no kēlā me kēia LED:
\[
V_{R} = V_{kumu} – V_f
= 5V – 2V
= 3V
\]
ʻO ke kumukūʻai resistor e kaupalena i ke au i kēlā me kēia LED:
\[
R = \frac{V_{R}}{I}
= \frac{3V}{20 \text{ mA}}
= \frac{3V}{0.02A}
= 150 \Omega
\]
No laila, pono kēlā me kēia LED i kahi resistor 150 ohm. ʻO ke au holoʻokoʻa e pono ai mai kahi lako mana 5V he 40 mA.
Ka hopena
He mau ʻāpana koʻikoʻi nā LED i nā mea uila hou ma muli o ko lākou hiki ke hāʻawi i nā kukui uila kūpono loa me ke ola lōʻihi. ʻO ka hoʻomaopopo ʻana i nā manaʻo kumu e like me ke kahe uila i mua, ke au, ka mana, ka pono quantum, a pehea e hoʻonohonoho ai iā lākou i loko o kahi kaapuni e hāʻawi i kahi kahua paʻa no nā noi kūpono. ʻO nā laʻana ma luna nei kahi hana mua i ka hoʻomaopopo ʻana i nā noi like ʻole a me nā helu e pili ana i ka hoʻohana ʻana i nā LED i nā kaapuni uila.
