This diagram is the circuit design traffic baton with LED flasher. It uses an astable multivibrator to flash the LED, it similar to flipflof circuit. The “on” time of the LED cluster is about 108 milli seconds and “off” time is around 105 milliseconds. The frequency is around 5 Hz. A diode is wired in series with the base of BD140 to increase the forward voltage in order to ensure that when BD139 conducts, BD140 is cut-off. Select the LED which consumes low current (20 mA or so) but flashes bright.