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| In the decimal numbering system, six digits are required to indicate the time. For example: At 48 minutes and 36 seconds past 10 o'clock, we write 10:48:36. This clock has 6 columns of lights, corresponding - left to right - to "tens of hours," hours, "tens of minutes," minutes, and "tens of seconds," seconds, the six digits required to display the time. Each column represents a decimal number value from 0 to 9. [The term for this use of binary numbers is "Binary-Coded Decimal," or "BCD."] The value of the decimal number represented in each column is determined by which lights in that column are ON i.e. which ones are lit: • The bottom light, if lit, is worth "1." • The one above it, if lit, is worth " 2." • The third one from the bottom, if lit, is worth "4." • The fourth one from the bottom, if lit, is worth "8". => You add the values of the ON light positions to get the final decimal value. All 10 possible values are shown in the diagram below. * * Hint: Remember the sequence: 1, 2, 4, 8 - bottom to top * * |
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| Note: The third (value = "4") and fourth (value="8") lights in a given column may not be there, depending on the maximum decimal value that column may have. For instance, after "59" seconds, the seconds counter cycles back to "00." Thus, the "tens of seconds" value never goes above "5." Since the maximum value -"5" - can be displayed as the sum of 4 and 1, only the "1" light and the "4" light are needed to display "5." No "8" light is needed for any "tens of seconds" number value. |
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To see an example of how to read the clock, go to: Example
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If your model had a "DIM" switch (located near the power plug inlet), it can be set to operate in "true" binary mode, as opposed to the default BCD mode. In binary mode, the bottom row of lights represents seconds, the second row up from the bottom represents minutes and the next row up represents hours (the top row is not used). See the figure 5 below. |
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