In the previous post, we saw how to make a 2Hz clock signal. However, for the seconds counter, we will need a 1Hz clock signal. In order to achieve this, I will clock down the frequency using a JK Flip Flop:
A Flip flop is a one-bit storage device which looks somewhat like this:
The truth table of this device looks somewhat like this:
Note that the flip flop toggles only on the rising edge of the clock. Therefore, in order to clock down the frequency by 2, we need to set the J and K bits high and feed the clock signal in to the CLK pin, thereby obtaining a 1Hz signal on the Q pin.
Adding the flip-flop to our circuit:
On adding the flip flop to our circuit, the schematic looks somewhat like this (The 4060 has been carried over from the previous post):
As calculated, this gives us a frequency of 1 Hz on the Q pin
This concludes our clock signal source. In the next post, we will have a look at counting seconds with the clock signal.