 The 7493 IC binary counter. The 7493 IC is an up counter that is capable of operating as a multi-modulus counter. It is constructed of two negative edge triggered counters that in their natural state are a mod 2 up counter and a mod 8 up counter. The mod 2 counter. Used by itself, flip-flop A operates as a mod 2 counter. The count begins with a zero at the Q output, and the maximum count occurs when the Q output is at a one. The counter recycles back to zero when the next clock pulse is applied. The mod 2 counter changes its count every time a negative edge of a clock pulse is applied to its clock input, which is labeled CLKA. The mod 8 counter. Flip-flops B, C, and D make up the mod 8 counter. The count begins at zero zero zero, with the maximum count at one one one, or the decimal equivalent seven, creating eight different counts. The mod 8 counter changes its count every time a negative edge of a clock pulse is applied to its clock input, which is labeled CLKB. The mod 16 counter. The 7493 IC can be made to operate as a mod 16 binary up counter by connecting an external wire from the mod 2 output QA to clock input B of the mod 8 counter, or by applying clock pulses to clock input A. The 7493 IC can operate at various modulus counts, other than 2, 8, or 16, by using two reset leads labeled R01 and R02. When logic highs are applied to both reset leads simultaneously, the count resets to zero zero zero zero. Under normal counts, both leads should be connected to a logic low. The mod 12 counter modification. The 7493 can be modified to operate as a mod 12 up counter, which means it will have 12 different counts from zero to 11. To operate as a mod 12 counter, QC and QD output leads are connected to R01 and R02. As soon as the binary count of one one zero zero, the decimal equivalent of 12 is reached, R01 and R02 are both high, which causes the counter to reset. The count of 12 is preset for only 40 nanoseconds, which is faster than what can be detected by the human eye. Therefore, 12 is not considered a valid count. We will apply 12 clock pulses and observe the count. You have completed this activity, the 7493 IC binary counter.