Page 26 - Template EBook Kita (A4 Document)

TOPIC 2: MONOSTABLE MODE

CIRCUIT OPERATIONS

Monostable mode has a stable state at LOW.

01 Initially, when the output at pin 3 is low, the discharge

transistor Q1 is ON and capacitor, C is shorted to ground.

02 When a negative pulse is applied to pin 2, the trigger input falls
below 1/3Vcc, the output of comparator 2 goes high which

resets the flip-flop and the transistor Q1 turns OFF and the
output at pin 3 goes high.

03 This is the transition of the output from a stable to an unstable

state. As the discharge transistor Q1 is OFF, the capacitor C

begins charging toward Vcc through resistance R.

04 When a negative pulse is applied to pin 2, the trigger input falls
below 1/3Vcc, the output of comparator 2 goes high which

resets the flip-flop and the transistor Q1 turns OFF and the
output at pin 3 goes high.

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