The circuit uses the CMOS 4060 14-stage binary counter with on board capability to include an astable. This is formed in IC1 using R2,3/C2/VR1. This sets the frequency to the required rate. The reason a fairly high frequency was used (as it could have been done with one IC) is that it is easier to build and calibrate an astable of around 50Hz rather than that of about 0.1Hz, and more accurate.
An LED is connected to Q5 giving a flash rate of 48Hz/ (2^5) = 1.5Hz showing that the counter is working. The clock to the second counter is taken from Q7, being 0.375Hz or one pulse every 2.6 seconds. This is further divided up to Q13 and Q14 which provide outputs that go high (the "on" part of the cycle) after 12 and 24 hours, giving the option to select either.
The output connects to a PNP transistor that will be conducting as long as the base is low, during timing, thus energising the relay until the timing is complete and the input goes high, thus releasing the relay and switching off the timer.
CN2 connects to the second set of contacts (SW3) of the relay so that any device can be switched to a maximum of 5A @ 12v or 2A @ 220vac. This should switch the live side of any device you want to control.
As soon as power is applied, R1/C1 reset the counters and the relay is energised, thus starting the timing..
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TIMINGS AND DIVIDER OUTPUTS
Output, 2^
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IC - Pin
|
Stage
|
Divisor
|
Low Time (sec)
|
Active
Time
|
1
|
1 -
|
Q0
|
2
|
0.0206
|
|
2
|
1
|
Q1
|
4
|
0.0412
|
|
3
|
1
|
Q2
|
8
|
0.0824
|
|
4
|
1
|
Q3
|
16
|
0.164
|
|
5
|
1
|
Q4
|
32
|
0.329
|
|
6
|
1
|
Q5
|
64
|
0.659
|
|
7
|
1
|
Q6
|
128
|
1.318
|
|
8
|
1
|
Q7
|
256
|
2.637
|
|
9
|
2
|
Q0
|
512
|
5.273
|
|
10
|
2
|
Q1
|
1024
|
10.55
|
|
11
|
2
|
Q2
|
2048
|
21.09
|
|
12
|
2
|
Q3
|
4096
|
42.19
|
|
13
|
2
|
Q4
|
8192
|
84.38
|
1 min, 24 sec
|
14
|
2
|
Q5
|
16384
|
168.8
|
2 min, 49 sec
|
15
|
2
|
Q6
|
32768
|
337.5
|
5 min, 38 sec
|
16
|
2
|
Q7
|
65536
|
675
|
11 min, 15 sec
|
17
|
2
|
Q8
|
131072
|
1350
|
22 min, 30 sec
|
18
|
2
|
Q9
|
262144
|
2700
|
45 min
|
19
|
2
|
Q10
|
524288
|
5400
|
1 hrs, 30 min
|
20
|
2
|
Q11
|
1048576
|
10,800
|
3 hrs
|
21
|
2
|
Q12
|
2097152
|
21,600
|
6 hrs
|
22
|
2
|
Q13
|
4194304
|
43,200
|
12 hrs
|
23
|
2
|
Q14
|
8388608
|
86,400
|
24 hrs
|
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