Logic circuits
Which correctly describes the operation of a D latch?
- AIt captures the input only at the instant of the rising clock edge
- BIt always outputs the inverted input
- CWhile the enable signal is active, the input passes straight to the output; when it becomes inactive, the value is held
Show answer and explanation
Answer: C. While the enable signal is active, the input passes straight to the output; when it becomes inactive, the value is held
A D latch is a level-sensitive storage element: while the enable (clock) is active, changes at the input appear at the output (transparent), and the value at the moment enable goes inactive is held. Capturing only at an edge is what a D flip-flop does, and one can be built from two latches.