Another disadvantage of the ring counter is that it is not self starting. Design and implement an asynchronous counter using decade counter ic to count up from 0 to n n decade counter circuit a binary coded decimal bcd is a serial digital counter that counts ten digits. Figure 1 shows the output waveforms of a decade counter. A decade counter is the one which goes through 10 unique combinations of outputs and then resets as the clock proceeds. It can produce output at the 10 pins sequentially, i. Digital electronics lab brcm college of engineering. Discussion in general electronics discussion started by vick5821, feb 11, 2012. Design and implement a ring counter using 4bit shift register and demonstrate its working. The output is a binary value whose value is equal to the number of pulses received at the ck input. Since 4 stages are required to count to at least 10, the counter must be forced to recycle before going through all of its states counts 1115. Now, reading from top to bottom, notice the alternating patterns of 0s and 1s in each place i.
There are many other type of counters rather than synchronous and asynchronous counters, such as decade counter, binary counter, ring counter, johnson counter, up down counter etc. Digital logic is rooted in binary code, a series of zeroes and ones each having an opposite value. The output of the counter can be used to count the number of pulses. The 74ls lowpower schottky family like the original uses ttl transistortransistor logic circuitry which is fast but requires more power than later families. A decade counter or a module10 counter goes through 10 unique output combination states until it resets. As it can go through 10 unique combinations of output, it is also called as decade counter. We can design digital triangular wave generator by using counters. Counter and types of electronic counters electrcial. It is a necessary part of the course at which attendance is compulsory. The counter generates four output bits whose logic levels correspond to the number in the count sequence. This circuit consists of one ip line, namely clock and number of op lines. With each clock pulse the outputs advance to the next higher value, resetting to 0000 when the output is 1001 and a subsequent clock pulse is received.
An ordinary fourstage counter can be easily modified to a decade counter by adding a nand gate as shown in figure 325. In digital logic and computing, a counter is a device which stores and sometimes displays the number of times a particular event or process has occurred, often in relationship to a clock. The counters four outputs are designated by the letter symbol q with a numeric subscript equal to the binary weight of the corresponding bit in the bcd counter circuits code. Bistable devices popularly called flipflops described in modules 5. Decade counter ics are available at mouser electronics. According to wikipedia, in digital logic and computing, a counter is a device which stores and sometimes displays the number of times a particular event or process has occurred, often in relationship to a clock signal. Seven7segment counter circuit with led displaydiagram. Thus weve designed sections on digital electronics video tutorial with the structure similar to professional courses. Chapter 11 digital to analog and analo g to digital converters. A decade counter has 10 states which produces the bcd code. A decade counter is an electronic circuit that counts in tens. Best author book of digital electronics online for engineering students. We may use some sort of a feedback in a 4bit binary counter to skip any six of the sixteen possible output states from 0000 to 1111 to get to a decade counter.
This circuit can be used in conjunction with various circuits where a counter to display the progress adds some more attraction. Decade counter counter circuit basics electronics for you. A decade counter counts a sequence of ten numbers, ranging from 0 to 9. The book digital electronics contains twelve chapters with comprehensive. Counters are used in digital electronics for counting purpose, they can count specific event happening in the circuit. Say, if we build a circuit with a decade counter with 10 leds. The name ripple counter is because the clock signal ripples its. What is a decade counter and what are some devices. I have studied three books on digital electronics till now.
Explore below some interesting electronic circuits based on ic cd4017. Design a modulus seven synchronous counter that can count 0, 3, 5, 7, 9, 11, and 12 using d flipflop. A counter is a device in computing and digital logic, that is used to store and display the particular event so many times. The values on the output lines represent a number in the binary or bcd number system. A decade counter counts ten different states and then reset to its initial states. Counter is a digital device and the output of the counter includes a predefined state based on the clock pulse applications. A binary mod 4 counter has 4 count states, from 000 to 011. This system facilitates the design of electronic circuits that convey information, including logic gates. It consists of 4 flipflops and requires additional circuitry to skip few states, toconvert the normal counter to a decade counter. If we need the decoded outputs, the ring counter looks attractive, in particular, if most of the logic is in a single shift register package. Ripple counter, asynchronous decade counter bcd ripple counter, synchronous counter, design of synchronous counter. Ncounter the 2bit ripple counter is called as mod4 counter and 3bit ripple counter is called as mod8 counter. Digital electronics part i combinational and sequential logic dr. Aims to familiarise students with combinational logic circuits sequential logic circuits how digital logic gates are built using transistors design and build of digital logic systems.
Digital electronics part i combinational and sequential. Home forums general electronics questions general electronics discussion 4017 decade counter reply to thread. Generally, counters consist of a flipflop arrangement which can be synchronous counter or asynchronous counter. Learning digital electronics with free video tutorials 2015.
An example of an integrated circuit that is of this type is the 4017 in the 4000 series cmos logic family. The modulus of a counter is the number of unique states through which the counter will sequence. Each output represents one bit of the output word, which, in 74 series counter ics is usually 4 bits long, and the size of the output. The ring counter had more stages, but was self decoding, saving the decode gates above. The ic cd40333 is a 5 stage johnson decade counter with decoder and is mostly used in digital displays. Chapter 9 design of counters universiti tunku abdul rahman. Asynchronous counter part1 digital electronics youtube. The 2bit ripple counter is called as mod4 counter and 3bit ripple counter is called as mod8 counter. A decade counter is a circuit in which each of the chip outputs are turned on, one at a time, sequentially or in succession. Digital electronicscounter wikibooks, open books for an.
The stress is given on the design of digital circuits. Counters types of counters, binary ripple counter, ring. Maini and published by john wiley and sons provides a comprehensive coverage of all the fundamental concepts, digital devices and integrated circuits and their applications in a very simple and easily understandable format. For the love of physics walter lewin may 16, 2011 duration. Bcd counter circuit using the 74ls90 decade counter. The 74hc family has highspeed cmos circuitry, combining the speed of ttl with the very low power consumption of the 4000 series. The basic decade counter is an electronic circuit with a 4bit binary output and an input signal called a clock. Notice that ff2 and ff4 provide the inputs to the nand gate. Electronics club 74 series logic ics families, 74hc. The values of the op lines denote a number in the bcd or binary number. Ic cd4017 circuits electronic circuits based on cd4017. A decade counter is a binary counter that is designed to count to 10 10, or 1010 2. Explain counters in digital circuits types of counters.
Typically, this type of counter has decoded outputs, meaning that it has 10 outputs, and each one goes high in sequence, all other being low. Two common types of counters are decade counters and binary counters. So in general, an nbit ripple counter is called as modulon counter. Counters, consisting of a number of flipflops, count a stream of pulses applied to the counters ck input. Digital electronics principles, devices and applications by anil k. Preface the book digital electronics contains twelve chapters with comprehensive material, discussed in a very systematic, elaborative and lucid manner. Salivahan i would recommend this book to beginners. Frequency dividers are the circuits which divide the input frequency by n any integer number, means if we provide some signal. Digital logic is the basis of electronic systems, such as computers and cell phones. The 74ls90 counting sequence is triggered on the negative going edge of the clock signal, that is when the clock signal clk goes from logic 1 high to logic 0 low. Draw the timing diagrams of the decade counter shown in fig. The mod of the counter represents the number of states of the cycles through it, before setting the counter to its initial state.
11 122 537 170 1503 752 179 345 1399 887 275 333 1581 877 1368 1008 150 1192 1258 514 1065 1052 1179 1145 1208 550 639 643 711 1490 1575 555 574 1529 1390 215 629 3 958 813 1100 1344 709 686 942 55 51