Class notes Electrical Engineering (EDS )

One-shots
A simple one-shot circuit.

, One-Shots

The one-shot or monostable multivibrator is a device
with only one stable state. When triggered, it goes to
its unstable state for a predetermined length of time,
then returns to its stable state. +V

REXT CEXT
For most one-shots, the length of time Q
CX
in the unstable state (tW) is determined RX/CX
by an external RC circuit. Trigger

Q
Trigger

Q
tW

, One-Shots
Nonretriggerable one-shots do not respond to any
triggers that occur during the unstable state.
Retriggerable one-shots respond to any trigger, even if
it occurs in the unstable state. If it occurs during the
unstable state, the state is extended by an amount
equal to the pulse width.
Retriggerable one-shot:
Trigger
Retriggers
Q
tW