These d-c triggered multivibrators feature output pulse-duration control
by three methods. The basic pulse time is programmed by selection of external
resistance and capacitance values (see typical application data). The '122
and 'LS122 have internal timing resistors that allow the circuits to be used
with only an external capacitor, if so desired. Once triggered, the basic
pulse duration may be extended by retriggering the gated low-level-active
(A) or high-level-active (B) inputs, or be reduced by use of the overriding
clear. Figure 1 illustrates pulse control by retriggering and early clear.
The 'LS122 and 'LS123 are provided enough Schmitt hysteresis to ensure
jitter-free triggering from the B input with transition rates as slow as 0.1
millivolt per nanosecond.
The Rint is nominally 10 k for '122 and 'LS122.
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