This video tutorial provides a comprehensive guide on how to construct a 39 LED circuit, controlled by a 555 timer and two transistors. The video thoroughly explains each step, ensuring you understand the underlying principles and practical execution.
Key Components and Circuit Overview
To begin, you’ll need components such as a potentiometer, resistors, and capacitors [00:12]. The heart of this circuit is the 555 timer, configured to operate as a multivibrator, which controls the blinking action of the LEDs [00:28]. The blinking speed is not fixed; you can adjust it by altering the resistance and capacitance values in your circuit [00:20].
Frequency Calculation and Control
The video details the formula used to calculate the precise blinking frequency, which depends on the chosen resistances and capacitance [00:38]. A table is also presented to help you with these calculations for various percentage values [01:43].
Transistor’s Role in Powering the LEDs
A crucial element highlighted in the video is the use of two transistors. These are essential because the 39 LEDs require more power than the 555 timer can supply directly [01:53]. Without these transistors, the voltage drop would prevent the LEDs from lighting up correctly [02:40]. The transistors efficiently manage the current flow, ensuring each LED receives adequate power [02:59].
Practical Circuit Building and Professional PCB
Initially, a laboratory-built version of the circuit is demonstrated [04:11]. The video emphasizes the use of a potentiometer to regulate both the frequency and intensity of the light emitted by the LEDs [04:17]. Due to some challenges with the self-made circuit, the video transitions to using a professionally manufactured printed circuit board (PCB) [04:28]. JLCPCB is mentioned as the tool used, owing to its user-friendly circuit designer interface [04:46]. The final design of the circuit, along with its Gerber file, is showcased [04:55]. The video also briefly covers the delivery process of the manufactured PCBs, noting the secure packaging [05:14].
Final Demonstration
The tutorial culminates in a demonstration of the fully assembled and functional LED circuit [06:30], where all components are working together harmoniously.
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