Driving A Bicolor LED

Description

Bicolor LEDs usually contain both GREEN and RED LEDs, which can be connected 'inversely parallel' in the kit driving the LED. Accordingly, the LED illuminates green when the current moves one way through the device, whereas the LED lights red if it travels the other way.

The Driving A Bicolor LED Kit is similar to some flasher circuits using IC555 as an Astable multivibrator. The only difference lies in the way it flashes using bi-color LEDs. When output at pin 3 of IC 555 goes high it operates on a group of LEDs. By inverting the IC’s low output by PNP transistor BC557 the other group of LEDs is made to flash.

This LED Circuit Tool alternately flashes a red/green bi-colored LED. When the output of pin 3 of 555 timer IC is high then the potential difference across the NPN transistor BC557 and pin 3 will same so there will be no current flow across the transistor so the green LED will be turn off.