Laporan ini memberi tumpuan kepada diod pemancar cahaya ultraviolet (UV LED) untuk sumber cahaya UV. Sumber cahaya UV adalah merujuk kepada aplikasi yang menggunakan lampu UV LED dengan panjang gelombang 405nm. Pemacu LED ialah litar elektronik yang mengawal kuasa untuk LED tunggal atau rentetan LED. Arus terus (AT) mesti digunakan untuk memastikan LED dihidupkan. Apabila bekalan voltan berlebihan digunakan untuk menghidupkan LED, ia akan merosakkan LED kerana arus yang mengalir melebihi arus ke hadapan LED tersebut. Oleh itu, AC ke DC penukar voltan keluaran sebanyak 5V diperkenalkan dan digunakan untuk membekalkan UV LED pemacu. Topologi AC ke DC ini dicipta kerana ia adalah cara inisiatif untuk menghidupkan UV LED memandangkan keluarannya ditetapkan untuk 5V. Nadi modulasi lebar (PWM) telah digunakan untuk mengawal kecerahan LED UV. Kitar tugas ditetapkan untuk PWM bagi mengawal arus yang mengalir melalui UV LED. Projek ini menggunakan transistor tunggal LED pemacu dan asas transistor boleh dijadikan masukan PWM. Jika kitar tugas yang ditetapkan 100%, arus akan berada di maksimum iaitu 22mA dan jika kitar tugas ditetapkan kepada 50%, arus akan menjadi separuh iaitu 11mA. Kecerahan UV LED telah diperhatikan semasa pelarasanan kitaran tugas. Perbandingan antara teori pengiraan fluks bercahaya dengan pengukuran telah dianalisis. Terdapat 12.59% perbezaan antara nilai fluks bercahaya dikira dan nilai fluks bercahaya diukur disebabkan beberapa kesalahan berlaku semasa pengukuran.
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This thesis is focused on ultraviolet light emitting diode (UV LED) for UV light source. UV light source is referring to a lighting application that uses UV LED with 405nm wavelength. LED driver is an electronic circuit that regulates the power to single LED or string of LEDs. The direct current (DC) must be applied to ensure LED is turned ON. When high voltage supply is applied to LED driver, it will damage the LED due to current flow exceeds the forward current of LED. The current flow through the UV LED should not over than 22mA. Thus, AC to DC converter with output voltage is 5V is introduced and used to supply the UV LED driver. This AC to DC converter topology is created as it is initiative way to power up UV LED since its output is fixed to 5V. The PWM is applied to control the UV LED brightness. The duty cycle set to PWM to control the current flowing through the UV LED. This project deals with single transistor LED driver and the base of transistor can be input of PWM. If the duty cycle is set 100%, the current will be at maximum which is 22mA and if the duty cycle is set to 50%, the current will be half which is 11mA. The brightness of UV LED has been observed during adjustment of duty cycle. The theoretical calculation of luminous flux is compared with the measurement and the difference between both have been analyzed. There is 12.59% difference between calculated luminous flux value and measured luminous flux value due to some errors that occurred during measurement.
Uv light source using uv led / Mohamad Suhairul Md Salleh