ONE_BUTTON_LATCHING_SWITCH

Published:2009/7/14 12:13:00 Author:May | From:SeekIC

The SET and RESET inputs are grounded, the inverted (-Q) output is fed back to the D input, and the pulses go into the CLOCK input. Each positive pulse makes the flip-flop toggle from one state to the other. The TLC555 chip in the ftgure serves two purposes. It inverts the pulses so that you can get a positive pulse from a switch that is connected to ground. More importantly, it also debounces the switch. When you press a button, it doesn't just make contact once-the contacts bounce, opening and closing three or four times. The 4013 would toggle once on each bounce, leading to unpredictable results. Thp TLC555 uses a resistor and capacitor to smooth out these fluctuations so that each press of the button produces only one pulse.



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