LEDs or Lamps Sequencers

  
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The purpose of this circuit was to create a ring in which LEDs or Lamps illuminate sequentially. Its main feature is a high versatility: you can build a loop containing any number of LEDs or Lamps, as each illuminating device has its own small circuit. The diagrams show three-stage circuits for simplicity: you can add an unlimited number of stages
LEDs or Lamps Sequencers - schematic

(shown in dashed boxes), provided the last stage output was returned to the first stage input, as shown. P1 pushbutton purpose is to allow a sure start of the sequence at power-on but, when a high number of stages is used, it also allows illumination of more than one LED or Lamp at a time, e. g. one device illuminated and three out and so on. After power-on, P1 should be held closed until only the LED or Lamp related to the module to which the pushbutton is connected remains steady illuminated. When P1 is released the sequencer starts: if P1 is pushed briefly after the sequence is started, several types of sequence can be obtained, depending from the total number of stages. If you intend to use lamps drawing more than 400mA current, BC337 transistors should be substituted by Darlington types like BD677, BD679, BD681, 2N6037, 2N6038, 2N6039 etc. A similar design appeared in print about forty years ago. It used germanium transistors and low voltage lamps. I think the use of LEDs, silicon transistors, Darlington transistors and 24V supply an interesting improvement.



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