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Component 2: Sequential systems

3 dot points across 3 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How are D-type flip-flops connected to make a binary counter, and what is its timing diagram?

Building a 1-bit and a 2-bit binary up-counter from rising-edge-triggered D-type flip-flops, how each stage divides the clock frequency by two, and reading the count from a timing diagram.
A focused answer to WJEC Eduqas GCSE Electronics on binary counters, covering building 1-bit and 2-bit counters from D-type flip-flops, how each stage halves the clock frequency, and reading the count from a timing diagram.
9 min answer →

How does a D-type flip-flop store and transfer a bit on a clock edge?

The rising-edge-triggered D-type flip-flop: how it copies its D input to its Q output on the rising edge of the clock, its use as a data latch and for data transfer, and reading its behaviour from a timing diagram.
A focused answer to WJEC Eduqas GCSE Electronics on the rising-edge-triggered D-type flip-flop, covering how it copies D to Q on the clock edge, its use as a latch and for data transfer, and reading timing diagrams.
9 min answer →

How do decade counters, decoder/drivers, seven-segment displays and the 4017 produce a counting display or sequence?

BCD and decade counters, the seven-segment display with its decoder/driver to show decimal digits, the 4017 decade counter as a sequencer with one output high at a time, and resetting a counter early to make a custom count length.
A focused answer to WJEC Eduqas GCSE Electronics on decade counters and displays, covering BCD and decade counters, the seven-segment display and its decoder/driver, the 4017 sequencer, and resetting a counter to make a custom count length.
10 min answer →