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C − Capacitance −

µF

10

1

100

10

1

0.1

0.01

0.001

Time − 0.1 ms/div

Capacitor Voltage

Output Voltage

Input Voltage

See Figure 9

Astable Operation

Time − 0.5 ms/div

t

H

Capacitor Voltage

Output Voltage

See Figure 12

C = 0.15

µF

GND

OUT

CONT

RESET

DISCH

THRES

TRIG

C

Output

0.01

(5 V to 15 V)

(see Note A)

NOTE A: Decoupling CONT voltage to ground with a capacitor can

improve operation. This should be evaluated for individual

applications.

Open

5

8

4

7

6

2

3

1

Pin numbers shown are for the D, JG, P, PS, and PW packages.

NA555, NE555, SA555, SE555

PRECISION TIMERS

SLFS022G – SEPTEMBER 1973 – REVISED MARCH 2008

Figure 10. Typical Monostable Waveforms

Figure 11. Output Pulse Duration vs Capacitance

the threshold input causes the timer to self-trigger and run as a multivibrator. The capacitor C charges through

This astable connection results in capacitor C charging and discharging between the threshold-voltage level

(

≈0.67 × V

times (and, therefore, the frequency and duty cycle) are independent of the supply voltage.

Figure 12. Circuit for Astable Operation

Figure 13. Typical Astable Waveforms

10

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Product Folder Link(s): NA555 NE555 SA555 SE555