TM9-4935-481-14-1
C4
(2) Retriggerable monostable multivibrator. (MIS-12837/11B) Monostable multivibrator is a circuit which generates a
single pulse at the output upon sensing a low-to-high transition at the positive transition input or high-to-low transition at the
negative transition input (see fig. 3-18).
(a) This monostable multivibrator has four inputs, two active HIGH and two active LOW. This allows a choice of
leading edge or trailing edge triggering. The TTL inputs make triggering independent of input transition times. When input
conditions for triggering are met, a new cycle starts and the external capacitor is rapidly discharged and then allowed to
charge. Active pull-ups are provided on the outputs for good drive capability into capacitive loads.
(b) The following operation rules apply to the multivibrator.
1. An external resistor (RX) and external capacitor (CX) are required as shown in the logic diagram of figure
2. The value of RX may vary from 5.0 to 50KW.
3. CX may vary from 0 to any necessary value available.
4. The output pulse width (t) is defined as follows:
t = 0.32 RXCX [1 + 0.7 ]
RX
where RX is in KW, CX is in pfd and t is in nsec.
(3) Clock flip-flop. (MIS-18698/027-01-Z)(fig. 3-19) A clocked flip-flop consists of two directly coupled flip-flops,
operating on the "master-slave" principle. The input information is stored in the "master" flip-flop when the clock voltage is
high, and is transferred to the "slave" when the clock voltage is low. This clocked flip-flop can be operated in either the R-S
or J-K mode. For J-K operation, the Q output is connected to a clear input, and the Q output is connected to a set input.
Asynchronous inputs, direct set (SD) and direct clear (CD), override the synchronous inputs. No matter what other inputs are
applied to the flip-flop, the direct set and clear inputs prevail.
(4) Dual J-K flip-flop. (MIS-18698/114-01) (fig. 3-20) Each section of this dual J-K clocked flip-flop consists of two
directly coupled flip-flops operating on the "master-slave" principle. Operation depends only on voltage levels, so the rise
and fall times of the input clock are unimportant in determining the state of the flip-flop. Input information is stored in the
"master" flip-flop when the clock voltage is high and is transferred to the "slave" when the clock voltage goes low. This flip-
flop has a common clock input which makes this device suitable for clocked counters and shift register applications. A
common direct clear (CD) and
Figure 3-18. Monostable multivibrator
3-22
