Led Flasher with the LM3909 IC streampowers
Introduction The LM3909 is an integrated circuit (IC) which will flash a light-emitting diode (LED). Using only two extra components and a battery, the circuit is cheap and has a very low current drain from a 1.5 V cell. The circuit can be used as a novelty flasher, an indicator for a dummy alarm bell box, or it could be attached to a torch so that it could be found easily in the dark! The simple circuit Led Flasher with the LM3909 IC Diagram Assembly The circuit can be built on a small piece of Veroboard (the piece shown in Figure 2 measures 15 holes by 10 strips). Using such a board, follow these instructions. 1. Depending on how far away you want the LED from the circuit board, solder a length of insulated wire to each lead of the LED. Use different colours of insulation – say, red and black, connecting the red lead to the anode (a) lead (the longer one) of the LED, and the black one to the cathode (k). Figure 2 shows these leads. 2. Cut the copper tracks as shown i...