portalia Posted December 7, 2004 Report Share Posted December 7, 2004 I'm trying to design a logo with led's, but i wanted to be able to flash the led's in sequence and then all the led's stay all lit until power is cut off.please see attached... Quote Link to comment Share on other sites More sharing options...
trampe Posted December 27, 2004 Report Share Posted December 27, 2004 All you have to use is a CMOS 4011, 4017 and 3 of SCR.Use the 4011 as an oscillator and the 4017 as the counter.Output of 4017 goes to SCR.If problems let me know and I will draw the schematic for you. Quote Link to comment Share on other sites More sharing options...
ante Posted December 27, 2004 Report Share Posted December 27, 2004 Hi trampe,Are you sure you can use SCR:s here, it Quote Link to comment Share on other sites More sharing options...
surajbarkale Posted December 29, 2004 Report Share Posted December 29, 2004 Ante,SCR's gate only serves to turn it on. Only way to turn off the SCR is to interrupt current flowing through it. And this is the requirementthen all the led's stay all lit until power is cut off. Quote Link to comment Share on other sites More sharing options...
ante Posted December 30, 2004 Report Share Posted December 30, 2004 Hi Suraj,Yes, if it means cut all the power not only the control power there is of course no problem. However this is not the only way to shut down the SCR. ;D Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted December 30, 2004 Report Share Posted December 30, 2004 If you take the gate below the cathide voltage the scr will turn off. Quote Link to comment Share on other sites More sharing options...
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