The Rotating LED Array Circuit using IC 555 described here is cleverly designed to work as an LED flasher, which can create a cool rotating light effect if the LEDs are set up correctly.
This LED design is simple but very effective making it great for different uses like decoration, emergency lights, or visual alerts.
The circuit works by using two IC 555 timer chips that produce pulse signals, making the LEDs flash in a pattern.
It runs on a small 3V battery, so it does not use much power.
Circuit Working:

Parts List:
Component | Value/Specification | Quantity |
---|---|---|
Resistors (1/4W unless specified) | ||
Resistor | 10k | 1 |
Resistor | 150Ω | 1 |
Resistor | 100k | 3 |
Resistor | 10Ω | 12 |
Capacitors | ||
Ceramic Capacitor | 10nF | 1 |
Electrolytic Capacitor | 1µF 25V | 1 |
Electrolytic Capacitor | 100µF 25V | 1 |
Semiconductors | ||
IC | 555 Timer | 2 |
LED (5mm, 20mA) | Any color | 13 |
Other Components | ||
On/Off switch | – | 1 |
Battery | 3V | 1 |
The circuit diagram here uses two IC 555 timer chips and both are set up to work as astable multivibrators.
The first IC1 555 timer creates a clock pulse that controls how the first set of LEDs blink.
At the same time the second IC2 555 timer, which is linked to the first one generates a different pulse signal with a unique frequency managing the lighting of the second set of LEDs.
The 555 Timer IC1 works as an astable multivibrator producing a square wave signal that makes the LEDs from LED1 to LED6 turn on and off at a steady pace.
On the other hand the second 555 Timer IC2 also acts as an astable multivibrator but it has a different timing cycle than the first one which controls the second group of LED7 to LED12.
Moreover a capacitor C3 is added to the circuit to help smooth out any voltage changes and there is an extra LED13 connected with a R17 150 ohm resistor that acts as an indicator light which remains permanently ON.
The synchronized blinking of both timers creates a cool rotating light effect of flashing LEDs, making a really eye catching movement.
To get the rotating effect you need to place the LEDs on a plastic sheet following the layout shown in the LED arrangement picture below.

Formulas with Calculations:
The formulas with calculations for Rotating LED Array Circuit using IC 555 is mentioned below:
The frequency of the IC1 555 astable multivibrator is given by the formula:
f = 1.44 / ((R13 + 2 * R14) * C1)
The duty cycle (D) is calculated as:
D = (R13 + R14) / (R13 + 2 * R14)
where,
- R13 = 10kΩ
- R14 = 100kΩ
- C1 = 1µF
Substituting the values into the formula:
f = 1.44 / ((10k + 2 * 100k) * 1µF)
= 1.44 / ((10k + 200k) * 1µF)
= 1.44 / (210k * 1µF)
= 1.44 / 0.21
= 6.86 Hz
This means the LEDs will flash approximately 6 to 7 times per second.
Similarly, for IC2 555 timer the frequency and duty cycle can be calculated using the same formula by replacing the resistor and capacitor values accordingly.
How to Build:
To build a Rotating LED Array Circuit using IC 555 following steps are required to be followed:
- Gather all the components as mentioned in the above circuit diagram:
- Connect pin 1 of IC1 to the GND of the circuit
- Connect pin 2 of IC1 to pin 6 of IC1
- Connect pin 3 to one end of resistor R1 and other end connect to cathode of LED1 and anode of LED1 connect to positive supply of the circuit and repeat the same with all the resistors R2 to R12 with LED2 and LED12
- Connect pin 4 and pin 8 of IC1 to positive supply of the circuit.
- Connect resistor R14 one between pin 6 and 7 of IC1.
- Connect resistor R13 from pin 7 and positive supply of the circuit.
- Connect positive of capacitor C1 from pin 2 of IC1 and negative of C1 connect to GND of the circuit
- Connect pin 1 of IC2 to GND of the circuit.
- Connect pin 2 and pin 6 of IC2.
- Connect pin 3 pf IC2 to one end of resistor 7 and other end connect to cathode of LED7 and anode of LED7 connect to positive supply of the circuit, repeat the same with remaining resistors R8 to R12 and LED8 to LED12.
- Connect pin 4 and pin 8 of IC2 to positive supply of the circuit.
- Connect resistor R15 from pin 2 of IC2 and positive supply of the circuit.
- Connect resistor R16 from pin 6 of IC2 and GND
- Connect one end of capacitor C2 from pin 3 of IC1 and other end connect to pin 2 of IC2
- Connect anode of LED13 to positive supply and cathode of LED13 to GND through resistor R17
- Connect a On/ Off switch from positive supply of 3V battery and negative of battery connect to GND of the circuit.
- Connect a positive capacitor C3 to positive supply of the circuit and negative of capacitor C3 connect to GND
Conclusion:
This Rotating LED Array Circuit is a cool and easy design that uses two IC 555 timer chips to create blinking lights that switch back and forth with rotating effect.
You can use it for different things like decorations, emergency lights or even in toys.
It works well with a low voltage battery and looks great with its flashing lights that change patterns.
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