And it resets for every new clock input. A BCD counter can count , , , , , , , , , , and and so on. A 4 bit binary counter will act as decade counter by skipping any six outputs out of the 16 24 outputs. There are some available ICs for decade counters which we can readily use in our circuit, like 74LS It is an asynchronous decade counter. The above figure shows a decade counter constructed with JK flip flop.
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There multiple kinds of counters which we can use in devices for binary or decimal counting. The IC 74LS93 counts from to in binary which is 0 to 15 in decimal.
In decimal, we only need 0 to 9 which covers all the possible values of decimal without giving any extra value. The counter starts counting from to and then it resets the value again. The automatic reset makes the counter to start from 0 and end at 9 in decimal. In IC we have four reset pins from which we can enable the counter by activating specific two pins. R1 Pin 2 Pin 2 is used as a reset pin in the IC.
It will show the maximum value on the output. It will use with the Pin 3. R2 Pin 3 Pin 3 is also used as a reset pin in the IC. It will use with Pin 2. R3 Pin 6 Pin 6 is used as a reset pin in the IC.
It will clear all the outputs with R4. R4 Pin 7 Pin 7 is also used as a reset pin. It will clear all the outputs with R3. QC Pin 8 Pin 8 is an output pin. It is used to give the second bit of 4-bit output data. QB Pin 9 Pin 9 is also an output pin. GND Pin 10 Pin 10 is a ground pin. It is used as a common ground with the circuit.
NC Pin 13 Pin 13 is a no connection pin. It will have no effect on the IC like pin 4. The IC has the ability to start from 0 and end at 9 automatically. The IC has low power consumption. The operating temperature range for IC is 0 to In this section working of will be explained.
There are two clock pins and they will be used to change the output state. When we are going to use the IC then we need to understand the reset pins first. These four reset pins will be used to control the output. These four reset pins will come up with multiple 16 combinations but in some combinations, there will be fixed output.
Decade Counter (BCD Counter)
74LS90 Decade Counter Pinout and Examples