In this post we learn how to build a simple yet accurate timer circuit using the IC and some ordinary passive components. Main Advantage of using IC as the Timer IC I have already discussed this IC comprehensively in one of my previous articles, everything regarding its pin outs have been discussed there in detail. We studied that the IC is specifically suited for timer applications and also as an oscillator. Other than the IC you would require just a couple of resistors, one pot and a capacitor for making this timer. Referring the figure, the simplicity of the design becomes evident and therefore this circuit is perfectly suited for all electronic newcomers, who can easily build this project and enjoy its useful service. As explained earlier in one my articles, the IC has an in built oscillator that needs just a few passive external components for making it tick.
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When it is high, the circuit will not receive clock signals and the counter will not count. On every positive edge of a clock, counter value gets increment by 1. As this CD is a 5-stage decade counter. Therefore its most basic use is in counting applications. It can turn on its 10 outputs sequentially according to time and frequency at CLK input pin. In this project, the decade counter IC increments the counter value on every clock pulse and the output pins gets high one by one.
CD IC is best for projects that require a sequential counting pattern. How to use CD? Pin 13 which is clock enable pin is kept LOW otherwise it can halt the clock signal.
This pin is responsible for resetting the counter to restart the counting from 0. Therefore, for normal operation of a circuit, these two pins are kept LOW. Similarly, this range can be increased to 30, 40, …, 10N numbers.
It will remain HIGH for 5 counts then will go down to 0 volts. When the count reaches 10, it will go HIGH again. The timing diagram indicating the behavior of all the outputs on different inputs is given below: Example Circuits In this section, we will see some example circuit using CD Counter. Therefore, we will display output of counter on LED bargraph. As we mentioned earlier, output pins Q0-Q9 give logic high signal sequentially. Output transition occurs on every positive edge of clock cycle.
The rate of output change depends on clock frequency. The maximum operating frequency which CD supports is 10MHz. Further, we can control output with the help of Enable pin. For example, if input to enable pin is active high, output will halt.
Therefore output will not change even on positive clock edge. Additionally, if you want to reset the output, MR pin can restart the counting. We will provide clock signal through timer IC.
CD4060 14-stage Binary Ripple Counter
CD has an inbuilt oscillator whose value is determined by the external capacitor connected to pin 11 and resistances connected to its pin 9 and pin Time delay can be changed by varying the value of capacitor or resistor. But all output pins states will not change according to this time period. However, they will change state in multiple of this oscillator time period. We will explain this in the next section. To start the oscillator, Turn ON the power supply.
CD4017 Counter IC Examples