Since you have already anticipated, this particular decorative flashing LED circuit signifies no more or less than a technique of lighting up a number of LEDs.
Circuit Description
The diagram displays five LEDs, but this is certainly prolonged to a maximum of ten by hooking up the reset line (demonstrated attached to output 5) to the next output, or, if ten LEDs are employed, by omitting the reset line once and for all.
Obviously, for every single additional LED a corresponding output phase comprising a transistor and a resistor will even need to be included.
Exactly what do the circuit carry out? Within the most basic design, each of the LEDs glow subsequently.
The rate in which this takes place is dependent upon the placing of potentiometer P1.
Additional sequences are available by incorporating a few clever little ' tricks'.
On the other hand, the essential configuration could possibly be beneficial, for instance, in the matter of a type of a road obstruction where each uses those yellow caution flashers which usually illuminate one after the other.
The diagram at A displays the way the LEDs can be designed to light and continue to be ignited one after another by merely including a diode among each and every output phase.
The cathode of the diode is attached to the base of T1 and also the anode is attached to the emitter of T2.
A second diode is attached involving the base of T2 as well as the emitter of T3 and so forth. This basic set up is fairly sufficient to generate the required result.
LEDs which usually illuminate in a 'to-and-fro' fashion can be acquired by simply linking the bases of the transistors to the outputs of IC2 within the subsequent way: The cathode of the first diode is attached to the base of T1 and the anode is attached to pin 3 of the 4017, Two diodes are attached to the base of T2, one would go to pin 2 and the other to pin 6.
In the same manner, T3 is linked to pins 4 and 5, T4 is linked to pins 7 and 1, and finally T5 is attached to pin 10.
By modifying the pin numbering a completely 'random' show sequence can be acquired.
Keep in mind that if more outputs are to be used the reset connection needs to be shifted to another location, unused output.
The results may also be put together: all kinds of ' strange and amazing ' sequences can be acquired simply by putting diodes between the outputs of 1C2 and the transistor bases and between the base of one and also the emitter from the following.
Currently most probably that this decorative flashing LED circuit is going to be designed by model builders and also require comparatively little electronic knowledge, a brief justification showing how the circuit functions could be beneficial.
Op amp IC1 produces squarewave pulses by constantly charging and discharging capacitor C1.
In the event the resistance of potentiometer P1 is increased the charge and discharge moment for this capacitor raises hence, frequency of the oscillator reduces - this particular leads to the particular LEDs getting ignited for more time durations.
The squarewave pulses are fed to a divide-by-ten counter, IC2.
The outputs of this counter each go high in turn after every clock pulse. The prior output, which has been high, right now runs low and the LED associated with it, via the resistor and transistor, goes out, even though the following LED within the series will come on.
Last but not least, when output five moves higher the counter is reset triggering a fresh series being commenced (LED D1 illuminates).
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