Dancing Lights

Here is a simple dancing light circuit based on NE555 (IC1) & CD4017 (IC2) .The IC1 is wired as an astable multivibrator to provide the clock pulses for the CD4017.For each clock pulse receiving at the clock input (pin14) of IC CD4017, the outputs Q0 to Q9 (refer pin diagram of CD 401) becomes high one by one alternatively.The LEDs connected to these pins glow in the same fashion to give a dancing effect.The speed of the dancing LEDs depend on the frequency of the clock pulses generated by the IC1.

Notes.

Assemble the circuit on a good quality PCB or common board.
The ICs must be mounted on holders.
The speed of the dancing LEDs can be adjusted by varying POT R2.
The capacitor C1 must be rated 15V.
Using different color LEDs could produce a better visual effect.

CD 4017 Pin configuration.

PWM lamp dimmer.

A simple and efficient PWM lamp dimmer using timer IC NE555 is discussed in this article. Yesterdays linear regulator based dimmers can only attain a maximum efficiency of 50% and are far inferior when compared to the PWM based dimmers which can hit well over 90% efficiency. Since less amount of power is wasted as heat, the switching elements of PWM dimmers require a smaller heat sink and this saves a lot of size and weight. In simple words, the most outstanding features of the PWM based lamp dimmers are high efficiency and low physical size. The circuit diagram of a 12V PWM lamp dimmer is shown below.

NE555 timer IC which is wired as an astable multivibrator operating at 2.8KHz forms the heart of this circuit. Resistors R1,R2, POT R3 and capacitor C1 are the timing components. Duty cycle of the IC’s output can be adjusted using the POT R3. higher the duty cycle means higher the lamp brightness and lower the duty cycle means lower the lamp brightness. Diode D1 by-passes the lower half of the POT R3 during the charging cycle of the astable multivibrator. This is done in order to keep the output frequency constant irrespective of the duty cycle. Transistors Q1 and Q2 forms a darlington driver stage for the 12V lamp. Resistor R4 limits the base current of transistor Q1.

Lightning LED's

The 555 is capable of sinking and sourcing up to 200mA, but it gets very hot when doing this on a 12v supply.
The following circuit shows the maximum number of white LEDs that can be realistically driven from a 555 and we have limited the total current to about 130mA as each LED is designed to pass about 17mA to 22mA maximum. A white LED drops a characteristic 3.2v to 3.6v and this means only 3 LEDs can be placed in series.

Milan Tomic

Hi. I’m Designer of Blog Magic. I’m CEO/Founder of Stuftech. I’m Creative App Developer, Web Designer, UI/UX Designer, Interaction Designer, Industrial Designer, Web Developer, Business Enthusiast, StartUp Enthusiast, Speaker, Writer and Photographer. Inspired to make things looks better.