A transparent latch
is an electronic
data storage device
with a data input, an enable input and a data output. Let us call these D, E and Q respectively. When E is high, Q = D. In other words, the latch is "transparent". When E is low, Q maintains the value it had when E was last high. In this state, the latch stores data.
In synchronous digital circuits, flip-flops are often preferred to transparent latches.
Transparent latches are available as integrated circuits, usually with multiple latches per circuit. For example, in the ubiquitous 7400 series of integrated circuits, type 7475 is a quadruple transparent latch.
See also: logic gate