rOmV4 - Logic Bistable Latch

Bistable Latch (Debouncer)

Also known as

RS Latch

RS Flip Flop

Bistable Flip Flop

Not S

Not R

Not Q

Comment

Unstable. Wil set or reset as soon as Not S or Not R goes high again.

If Not S is low, Q goes high and Not Q goes low.

If Not R is low, Not Q goes high and Q goes low.

0 or 1

1 or 0

Circuit remains in its previous stable state.

Here is the full circuit diagram and two alternative ways to draw the latch.

If the "NOT S" switch is pressed, the top input goes low and the top NAND gate output goes high and stays high.

If the "NOT R" switch is pressed, the bottom input goes low and the bottom NAND gate output goes high and stays high.

If both switches are pressed, both outputs go high until one or other of the switches is released.

This is good for debouncing because if R or S are pressed multiple times, only the first press has any effect.

Subject Name Level Topic Name Question Heading First Name Last Name Class ID User ID

Q: qNum of last_q Q ID: Question ID Score: num correct/num attempts Date Done

Question Text

image url

Help Link

Add Delete Clone Edit Hardness

Help Text

Debug

You can attempt a question as many times as you like.
If you are logged in, your first attempt, each day, is logged.
To improve your scores, come back on future days, log in and re-do the questions that caused you problems.
If you are logged in, your most recent wrong answers get remembered. This might help you and your teacher to correct your understanding.
In the grade book, you can delete your answers for a topic before re-doing the questions. Avoid deleting unless you intend re-doing the questions very soon.

Hosted at linode.com - London

Please report website problems to Neil