Bike turning Signal Indicator

The objective of this circuit is to indicate left or right turn for bike/vehicle. Two identical circuits are needed, one is for left and the other is for right. The main heart of this circuit is 555 timer. Here, this 555 timer acts as an astable multi vibrator. It generates the pulse signal with variable width. Using this variable width of the pulse, we can set different time delays for the LEDs (ON and OFF for LEDs). HOW IT WORKS The circuit consists of three 47k resistors, which are connected to 555 timer and these are used to set the time delay for LEDs.The diode is connected in reverse bias at the output to maintain constant current at the output. BC547 (NPN) Transistor switches the LEDs ON and OFF based on the base currents. 330 ohm resistors are used to drop the voltage otherwise LEDs may get damaged. Here we can vary the time width of output pulse by varying the resistance or capacitance value.

published 10 years ago