# 555 IC LED Flasher for Up To 10 LEDs

This LED flasher circuit uses 555 IC, and is capable of driving up to 10 LEDs. The good news is, the use of multiple LEDs in series doesn’t increase the power consumption when compared with using only two LEDs. If we use only two LEDs, then we have to sink the power into a current limiter resistor, which dissipate the power into heat.  With the use of 10 LEDs, now almost all the power will be converted into light by this  flasher circuit, and only small portion will be dissipated through current limiter resistor. Here is the schematic diagram of the circuit:

The flashing frequency is determined by 47uF capacitor, as well 4.7k and 15k resistors. To modify the flashing rate, you can change the values of these capacitor and resistors but you should keep the 4.7k resistor replacement above 1k to avoid 555 IC get damaged when pin 7 is internally shorted to ground at the discharging cycle. Please also note that the timing of two alternating LEDs is not symmetric. You can see that the charging time of the 47uF capacitor is determined by the two resistors (4.7k + 15k), but the discharging is determined only by the 15k resistor. To approach the symmetric timing for both group of flashing LEDs, if you want to change the resistor values, then you must keep the 4.7k resistor small eanough compared to the 15k one. The resitors R1 and R2 is determined by the supply voltage and the number of LEDs in each group.Use the following formula:

R=[Supply_voltage – (LED_voltage * NumberOfLEDs)] /LED_current

For example, if we use a 13.6V supply voltage, with 5 red LEDs  (LED_voltage = 2V) for the upper LED group, and we want to operate the LED at 15 mA), then we should compute the value of R1 as:

R1 = [13.6V-(2V *5)]/0.015A)

R1= 3.6 V/0.015 A = 240 Ω

[Circuit’s schematic diagram source: seekic.com]

This entry was posted in Lighting and LED Circuit and tagged , , . Bookmark the permalink.,
Possibly Related to "555 IC LED Flasher for Up To 10 LEDs" Circuits

• LED Flasher Using Transistor
This simple LED flasher circuit will turn ON and OFF two LED alternatively. The first LED will turn ON when the second LED is OFF for some period, then the first led will turn OFF and the second LED will … Continue reading →...
• Led Flasher Circuit Using 555 IC
LED flasher circuit can be built based on 555 IC. Using 555 IC, the flashing rate can be more flexible to adjust.  This LED flasher circuit is similar to our transistor flasher circuit, but the flashing period of both LEDs … Continue reading →...
• Blinking LED Emulates Incandescent Bulb
This is flashing LED circuit emulate the turning of incandescent lamp.  The characteristic of incandescent lamp is that they can’t abruptly change the luminosity. This circuit is used to fade in and fade out the on and off state change.   … Continue reading →...
• Power FET Lamp Flasher
As an alternative to bipolar transistor, a lamp flasher can be built by using two power FETs.  Like other flasher circuit, this circuit alternately switch the two lamps off and on.  It is based on a simple astable multivibrator that … Continue reading →...
• 1.5V LED FLasher Using 3 Transistors
To make LED works, you need a voltage source that is higher than the LED’s forward bias voltage, and it’s higher that 1.5V (around 2V for red LEDs). Fortunately, now you can make a LED flasher circuit that needs only … Continue reading →...