Low Battery Indicator
It is an ideal solution to protect rechargeable batteries from deep discharge. It gives an LED indication when the voltage level in the battery drops below 5.1 volt.
CA 3140 Op Amp is used as a comparator with a zener to fix voltage in its non inverting input. Preset VR1 set the voltage level just below 5.1 volt at the inverting input. When the battery voltage is above 5.1 volt, zener provides regulated 5.1 volt to pin3 of IC and its output goes high to light LED. It indicates that battery is full. If the voltage in the battery drops below 5.1 volt, output of IC turns low to switch off LED.
Circuit designed by D.Mohan kumar
About the author
Mr. D. Mohan Kumar M.Sc., M.Phil, is a Selection Grade Lecturer in Animal Science. He has been guiding Post Graduate students in Animal Science research for the last 25 years in several premier institutions in Kerala, India. Presently he is working in the PG department of Zoology, Govt. College for Women, Trivandrum, Kerala, India.
He is an avid electronics enthusiast and has been designing circuits for the past 20 years. In this period he has supported many electronics/electrical engineering students in their final year projects.
He is a regular contributor to Electronics For You magazine which is South Asia's largest circulating electronics magazine published from New Delhi, India.
He has agreed to write articles for electroschematics.com on a regular basis.
