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www.play-hookey.com | Thu, 04-15-2021 |
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Direct Current
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Alternating Current
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Semiconductors
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Digital
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Logic Families
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Digital Experiments
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Computers
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| Analog | Analog Experiments | Oscillators | Optics | HTML Test | |
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| Combinational Logic | Sequential Logic | Alternate Flip-Flop Circuits | Counters | Registers | The 555 Timer | | ||
| Basic 4-Bit Counter | Synchronous Binary Counter | Synchronous Decimal Counter | Frequency Dividers | Counting in Reverse | The Johnson Counter | |
Frequency Dividers |
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If we apply a fixed-frequency pulse train to a counter, rather than individual pulses coming at random intervals, we begin to notice some interesting characteristics, and some useful relationships between the input clock signal and the output signals.
Consider a single flip-flop with a continuous succession of clock pulses at a fixed frequency, such as the one shown to the right. We note three useful facts about the output signals seen at Q and Q':
The duty cycle of any rectangular waveform refers to the percentage of the full cycle that the signal remains at logic 1. If the signal spends half its time at logic 1 and the other half at logic 0, we have a waveform with a 50% duty cycle. This describes a perfect, symmetrical square wave.
Other counting sequences are also possible, of course. If a need exists to have two or more signals in a particular frequency relationship with each other, some extension or variation on the circuits shown here can be designed to supply the need.
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