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Decoration for the Christmas tree – LED toys

The device is recommended as a luminous decoration of the Christmas tree. In addition to traditional jewelry, it is always very nice to complement them with hand-made electronic gadgets. Introducing the device diagram – glowing bauble. The system is very simple. – LEDs are controlled from the counter. Due to the clock frequency, the illusion of flickering of all LEDs is created. Pulse mode ensures long-term operation of the toy, – if powered by battery. circuit Description

Schematic diagram of the device shown in Figure 1.

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Transistors T1 and T2, resistors R2 … R5 and capacitors C1 and C2 were used to create an unstable multivibrator, square wave, which is the synchronization signal of the ring counter system U1 (C4017). This is Johnson’s counter with 10 exits, on which the clock, output 14, circulating logical. The meter outputs power to the LEDs. Not hard to guess, that only one diode is lit at the same time, however, an unstable multivibrator generates a clock with such a high frequency, that the observer has the illusion of the simultaneous flashing of all diodes. This type of diode power supply was chosen because, that the system can run on battery and, in this way, significant energy savings have been achieved, which maximizes its working time. The frequency of the generator can be adjusted by changing the capacitance of capacitors C1 and C2 (10 NF … 1 mF). It should be borne in mind, that a higher operating frequency and longer lighting times increase the need for a power source.

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On the picture 2 the assembly diagram of such a trinket is shown. Used items are in SMD enclosures. A properly assembled device works immediately after connecting the power source. It must be in the range 5 … 12 DC. The brightness of the LEDs will be different for different supply voltages. It can be fixed, by changing the value of the resistor R1. An ideal effect is created by several or more than a dozen Christmas balls. Their power supply can be connected in parallel and powered by a single connected power source.. The hole next to the C3 capacitor is designed for hanging from a colored tape, whereby such toys on the Christmas tree will look even better.

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