TRIAC_TRIGGER

Published:2009/7/13 4:53:00 Author:May | From:SeekIC

National LM3909 IC is connected as pulse-transformer driver operating from standard 5-V logic supply. IC is biased off when logic input is high. With low logic input, IC provides 10-μs pulses for transformer at about 7 kHz. Trigger is not synchronized to zero crossings but will trigger within 8 V of zero for resistive load and 115-VAC line. Triggering oc cum at about 1 V, but trigger level can be changed by using other input resistors or bias dividers.- Linear Applications, Vol. 2, Na-tional Semiconductor, Santa Clara, CA, 1976, AN-154, p 7.



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