Ne555P General Purpose Timer (7C - Epson LQ-1050 Technical Manual

The 555 is a one circuit general purpose timer, which can be used to construct a timing generator circuit
such as a one-shot/multi oscillator using a few external parts.
Features
. Wide timing range (1.Ls to hours)
. Variable duty cycle
TTL compatible output
1
TRIGGER 2
OUTPUT 3
RESET 4
Fig. A-24. NE555P Pin Diagram
Reset
Independent from the
Low
voltage level
I
High
High > 4
High
Applications:
Monostable multivibrator, pulse width modulation circuit, a stable multivibrator, missing pulse detector,
and pulse position modulation circuit.
7 DISCARGE
6 THRESHOLO
5 CONTROL VOLTAGE
Table A-10. NE555P Function
Trigger
Independent from the
voltage level
Independent from the
voltage level
TRIGGER
Fig. A-25. NE555P Block Diagram
Threshold
A-25
DISCHARGE
Transistor for Timing
output
Capacitor Discharge
Low
I
High
Low
Holds the former state
REV.-A
ON
I
OFF
ON
I
I