Electronics 5b - Binary counters Flashcards
What does a D-type edge triggered flip-flop look like in a circuit?
This one is a falling edge flip-flop. If it was just C then its a rising edge triggered flip-flop.
What does a circuit for a shift register look like and whats its purpose?
Circuit shown
Explaination:
* Only carries the input along each flip-flop one after another.
* This can be useful for things lik train or bus displays that shift patterns across, to make the station signs etc.
What is the circuit for a binary counter and how does it work?
Circuit shown below.
Explaination:
* In each flip-flop, it’s NOT Q input is the input in D.
* The Q output for each flip-flop depends on the input of D when it was clocked.
* Notice that the clock is a rising edge trigger flip-flop, so we only get data changes when it goes from 0 to 1 on the clock.
* So if NOT Q is origianlly 1, then D is also 1, but Q is 0, so A is 0. when the clock ticks to 1, this then changes NOT Q and D to 0, and Q and A to 1.
* This now means that for the next flip-flop, the clock is set orignally, to 0, then once it changed to 1, the NOT Q changed to 0 which was the input for the clock on the B section. This means that no data change in D for B. But once the clock goes back to 0 and 1 once more in a cycle, the NOT Q goes back to 1 and so the D value of 1 in B can be entered.
* This is why the for A (0->1) takes 1 clock pulse, B takes 2 clock pulses, C takes 4 clock pulses, D takes 8 clock pulses.
* This is why it is used for a binary counter, look at the truth table. Remember read it from right to left for binary number in this case.
How can we make a divide by N counters circuit for everyday use?
The ‘divide by N counters’ works because each flip-flop connected one to the other will mean the effective frequency out, will be 2^N times less than the original clock frequency. That is somewhat how you can make digital clocks such as the one below.
What are some uses of Sequenctial logic and binary counters?
Memory chips, such as RAM, DRAM or flash memory.