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The 7490 integrated
circuit counts the
number of pulses
arriving at its input.
The number of pulses
counted (up to 9)
appears in binary form
on four pins of the ic.
When the tenth pulse
arrives at the input,
the binary output is
reset to zero (0000) and
a single pulse appears
at another output pin.
So for ten pulses in
there is one pulse out
of this pin.
The 7490 therefore
divides the frequency of
the input by ten.
If this pulse is applied
to the input of a second
7490 then this second ic
will count the pulses
from the first ic.
It will give one pulse
out after 100 pulses
have been applied to the
first ic.
The 7490 can be
connected to divide by
other values.
Decimal
Binary
0 0000
1 0001
2 0010
3 0011
4 0100
5 0101
6 0110
7 0111
8 1000
9 1001
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