Ok, for some reason uploading images doesn't want to work for me so I will do the best I can to describe my circuit:
It is the timing circuit for a simple digital clock. I have a CMOS 4060 set up with the appropriate resistors and crystal to generate a 2Hz signal. This then goes through a CMOS 4020 to divide it into a reliable 1Hz signal which is fed into my first counter IC. However, I have included a switch between the 1Hz output and the counter input. This allows me to switch (S1) the timers input between either the 1Hz output used to run the clock (S1 is in clocking position) and another input (S1 is in timing position) which I will explain now. The second input is controlled by 2 momentary switches. The first (S2) is connected directly to the positive supply line to allow the clock the increment by 1 second, the second (S3) is connected to the power supply of a 555 timer (the output of which is connected to the input for the timer when the S1 is in the timing position) to allow the user to fast-forward to roughly the time they want to have and then select it exactly with the 1 second increment button.
My problem:
When S1 is set to connect the 1Hz output to the timer, the first IC that generates the 2Hz output generates no output unless S2 is down. If S1 is set to connect the timer input to S2 and S3 then all switches function as normal. Can anyone suggest what might be the problem?
Crude Diagram:
It is the timing circuit for a simple digital clock. I have a CMOS 4060 set up with the appropriate resistors and crystal to generate a 2Hz signal. This then goes through a CMOS 4020 to divide it into a reliable 1Hz signal which is fed into my first counter IC. However, I have included a switch between the 1Hz output and the counter input. This allows me to switch (S1) the timers input between either the 1Hz output used to run the clock (S1 is in clocking position) and another input (S1 is in timing position) which I will explain now. The second input is controlled by 2 momentary switches. The first (S2) is connected directly to the positive supply line to allow the clock the increment by 1 second, the second (S3) is connected to the power supply of a 555 timer (the output of which is connected to the input for the timer when the S1 is in the timing position) to allow the user to fast-forward to roughly the time they want to have and then select it exactly with the 1 second increment button.
My problem:
When S1 is set to connect the 1Hz output to the timer, the first IC that generates the 2Hz output generates no output unless S2 is down. If S1 is set to connect the timer input to S2 and S3 then all switches function as normal. Can anyone suggest what might be the problem?
Crude Diagram:
Code:
A B
| |
| |
| |--|
|---<
|--| o------|
| \ |---|--------C
|--|----o | |
| |
| o
| \
| o
| |
D E
A = Input to timing IC
B = 1Hz output from IC
C = Positive supply line
D = Output from 555 timer
E = Power supply to 555 timer
|
o
\ = Momentary Switch (normally open)
o
|
|-- L1
C -< = SPDT Switch (connects C to L1 or L2)
|-- L2
Last edited: