TM 11-5805-424-15/NAVELEX 0967-220-9010/TO 31W2-2G-41
and positive triggering is achieved in a different
to the input of Rg and Ca, a differentiated
way ((2) below).
waveform (positive and negative spikes) is
applied to diode CRc, which passes only the
(2) Triggering. Diode CRa and resistor Rb and
positive spike to the base of transistor Qa.
diode CRb and resistor RC limit the input trigger
Resistor Rh, capacitor Cb, and diode CRd
to a +6-volt positive trigger.
perform the same function for transistor Qb. If
develops one input trigger, while capacitor Ca
the transistor associated with the positive inputs
provides a differentiated input to diode CRb.
is conducting when the positive trigger is applied
f. Two-Input Bistable With lnternal Gating and -6-
through its associated base diode, the transistor
will be cut off, causing the other transistor to
(1) General. Resistors Rc and Rd establish the
conduct, and thus change the state of the
initial bias for transistors Qa and Qb,
bistable. A second positive trigger must now be
respectively. Resistors Ra and Rb are the
applied to this on transistor to change the state
collector load resistors. Resistors Re and Rf and
of the bistable (that is, set it to its original state).
capacitors Ca and Cb provide for cross-coupling
c. Common Input Bistable With Collector Steering,
and determine the switching time for the stage
Type FFC- (B, fig. 5-1). The bistable multivibrator stage
to change state. The outputs (180out of phase
shown in B, figure 5-1, is essentially the same as that
with each other) are developed across the
collector and emitter of the two transistors.
resistors Rg and Rb are used to direct the common
Diodes CRa and CRb clamp the output to -6
positive input to the transistor that is conducting.
volts when the transistors are cut off.
d. Two-Input Bistable-Type FFE- (A, fig. 5 2).
(2) Triggering. Resistor Rg, capacitor Cc, and diode
(1) General. Resistors Ra. and Rb establish initial
CRc form a shaping AND gate that provides
bias for transistors Qa, and Qb, respectively.
positive triggers, exclusively, to the base of
Resistors Rd and Re provides the necessary
transistor Qa only when Qa is conducting (the
cross-coupling to allow the stage to change
positive trigger will turn Qa off). Resistor Rh,
state. The outputs (180out of phase with each
capacitor Cd, and diode CRd, perform the same
other) are developed across the collector and
function for transistor Qb when Qb is conducting.
emitter of transistors Qa and Qb, with resistors Rf
g. Two-input Bistable With Internal Gating, -6-Volt
and Rg, acting as the collector load resistors.
Output Clamp, and Collector Steering, Type FFG- (B,
Capacitor Ca is used as a speedup capacitor to
fig. 5-3). The FFG-type
is essentially the
insure rapid changeover when transistor Qa is
same as the FFA-type (b above), except that, for the
FFG-type, either one of two inputs may be applied as a
(2) Triggering. Resistor Rc serves as a limiting
common input to both transistors Qa and Qb. Diodes
resistor for one of the positive trigger inputs,
CRe and CRd provide for collector steering of both
with diode CR, used to pass only the positive
common inputs, allowing a positive trigger to be applied
input transitions. The input to the base of
through diode CRc or CRd (one input) or through diodes
transistor Qa is a positive trigger developed by
CRf or CRg (second input), the path depending on which
the previous stage.
transistor is conducting. Each output is clamped to -6
volts (by diode CRa or CRb) when a transistor is cut off.
e. Two-[n7pt Bistable with +6 Volt Output clamp,
h. Two-input Bistable With +6-Volt Output Clamp,
Type FFB- (fig. 5-4). The stage shown
in figure 5-4
(1) General. Operation of the FFF-type bistable is
essentially the same as the FFE
essentially the same as that of the FFE-type
bistable (d above). For the FFF-type, however,
the output voltage is clamped to -6 volts instead
of ground when the transistors are conducting,