Wednesday, 20 March 2013

DUAL MODE LED FLASHER



DUAL MODE LED FLASHER  

This LED flasher is built around timer 555.  The circuit is very simple and self depictive.  It is a free running oscillator, oscillating at 1 Hz rate approximately.  Transistor Q7 is used to control LED mode.  When high logic is given to the base of Q7, pin 2 of IC1 is pulled down below 2/3rd of VCC resulting in high output at pin 3 and LED D3 glows constantly.  The low logic at base of Q7 keeps LED flashing.  It can be connected to many circuits.  For example Automatic Battery Charger showing two states of  charger i.e. battery charging and battery charged.  It can be connected to 12 V battery charger as it is.  However, for 24 V charger any of combination shown in fig 2 or 3 may be added. Since IC 555 works fine if connected to +5 to +15 volts (Min-Max).

No comments:

Post a Comment