FLASHING_LED_EGG_TIMER

Published:2009/7/12 21:10:00 Author:May | From:SeekIC

UJT oscillator controlled by FET timer makes LED flash after time delay determined by value of R1. When 100μF capacitor charges to about 1 V after switch is turned on, MPF112 FET switches on and forms part of charging circuit for 2N2646 UJT oscillator which then pulses LED at about 200 mA peak. Although developed as inexpensive egg timer, circuit has many other applications.-J. Jeffrey, Simple FlashingL.E.D. Timer, Wireless World, Oct. 1974, p 381.



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Measuring_and_Test_Circuit/FLASHING_LED_EGG_TIMER.html

Print this Page | Comments | Reading(3)