Need help for a dawn/dusk LED circuit

Bernard

Joined Aug 7, 2008
5,784
This new print is all of the 120 AC and DRIVER parts of the schematic. Driver is turned off at completion of full cycle by 12 V relay. Timer controles 120 V AC relay , giving isolated sw, for logic. Dimming inputs D1 & D2 have no polarity specifications that I know of. D2 has an offset adjustment circuit controlled by 5k trim pot. Counter out " low " will have small + V so D-A will have a small + V @ reset, hence need for trim adj. With 5 LEDs per string it's possible that dimming will not be complete as mfg print shows 6 LEDs .May need to simulate one more LED with Si 1 A diodes *, probably not needed but something to watch for. LM324 selected for operation with single + supply. Q's used to identify all active components of logic. QF-1, is used as a buffer,hi inZ, lo out Z. QF-2 non inverting adjustable gain amplifier. Let the comments flow.
 

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Bernard

Joined Aug 7, 2008
5,784
Changes & corrections: 74C08 replaced 74C10; 120V relay contacts should be NC; FF is 4013; OSC, QA-2 & QE-1, period is about 1 RC[ 47μF,1 M pot. might do ]. A cycle starts when TIMER energises 120 V relay,contact origionally shown as NO, should be NC; open allowing .1 μF cap to charge toward +12 V .QE-2 switches state at .4V,amplified,inverted,differentiated neg pulse,inverted and shaped forming a reset pulse for counters & FF[Z's ]. QA-1 switches at about 6V giving a delayed + pulse later than reset[ hopefully],[ Y], setting FF hi, unblocking OSC, energising 12V relay , powering up DRIVER.
Having problem with attachment.
 

Bernard

Joined Aug 7, 2008
5,784
UP/DN got lost in correcting SW; Add a line from QE-2-6 to QD-10; now when SW opens,UP/ DN goes hi, enabling up count. Counting continues for 255 steps. QD-7, carry out, goes lo at full count,is inverted , fed to QE 3&4. QE-3 inputs both hi, out-hi [ pre-set enable ], loading hi's to all parallel inoputs & inhibiting count.LED's stay at full brightness for the duration of timing period [7.5 hrs +-]. SW closes,UP/DN goes lo, pre-set removed,count enabled, counter decrement down to all 0's, again CO goes lo, gated out of QE4-11 [X] goes hi, resetting FF QB-1-4[X].Output goes lo 12V relay off, OSC inhibited, LED's full dim. Will it work ??
Lettovers: 1/2 FF, 2 OP AMPs, ground inputs.
 
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