Universal electronic timer circuit diagram
Posted on Dec 11, 2010 3900
Figure 1-1 The general-purpose timer once timing of 5 minutes to 18 hours; the timing cycle from 5 minutes to 20 hours; the total time of the timing and the timing to open and
close 18 hours. Controlling power of 500W or less, the circuit power consumption is less than 1W. Time base circuit NE555 and C3, W, when R1, R2 constituting the base pulse generating circuit. W can adjust the pulse period from 5 minutes to 2 hours between changes. R2 extended from the pulse period of action. R2 is the longest period without a pulse for 1 hour. CD4017 counter and D2-D10, K1-K10 delay multiplier circuit and other components. The circuit will extend a total of 10 times the pulse period. K1-K10 control multiplication factor, and the NE555 output pulse period was logarithmic plot. BG and triac control circuit constituting the AC power. BG group high level conduction, SCR is triggered conduction, controlled circuit. BG base to very low cut-off, SCR is turned off, the controlled circuit to stop working. C1, DW, D11, C2 composed of simple DC supply circuit to provide 12V DC power for the timing circuit. When a timer, K12 set to 1 at the, K1 open. NE555 pulse output 10 after, CD4017s EN is high and stop counting. Then click the AN, CD4017 counted once again, once the timing up to 18 hours. When the timing cycle, K12 put 2, CD4017 cycle count. Each time through the loop the longest 20 hours. Timing of opening and closed by a timing control K1-K10.