Digital Logic Fundamentals Unit 5 – Flip-Flops
UNIT 5 – FLIP-FLOPS
UNIT OBJECTIVE
At the completion of this unit, you will be able to demonstrate the operation of a set/reset (RS)
flip-flop and a D-type flip-flop on the DIGITAL LOGIC FUNDAMENTALS circuit board by
using measured logic levels of the input and output signals.
UNIT FUNDAMENTALS
Flip-flop circuits have an output state of logic 1 (high) or logic 0 (low). Flip-flops are bi-stable:
they remain in one logic state until switched to the complementary (opposite) state. Logic 1
(high) is the complement of logic 0 (low).
Flip-flops function as memory or storage elements, synchronizing circuits, dividers, and system
reset elements. Flip-flop circuits are configured with basic logic gates or with an integrated
circuit (IC) having many gates.
There are several types of flip-flop configurations. This unit demonstrates the RS flip-flop
(set/reset) and D-type flip-flop. The schematic symbols are shown.
In general, flip-flop circuits have two outputs labeled Q and Q. The inputs include set (preset),
reset (clear), data, and clock signals.
The Q and Q outputs are complementary: when Q is high (logic 1), Q is low (logic 0) and vice
versa.