Time − 0.1 ms/div

Capacitor Voltage

Output Voltage

Input Voltage

C = 0.02

µF

See Figure 9

C − Capacitance −

µF

100 k

10 k

1 k

100

10

1

100

10

1

0.1

0.01

0.1

0.001

NA555, NE555, SA555, SE555

SLFS022I – SEPTEMBER 1973 – REVISED SEPTEMBER 2014

www.ti.com

Feature Description (continued)

Figure 14. Free-Running Frequency

8.3.3 Frequency Divider

By adjusting the length of the timing cycle, the basic circuit of Figure 9 can be made to operate as a frequency

divider. Figure 15 shows a divide-by-three circuit that makes use of the fact that re-triggering cannot occur during

the timing cycle.

Figure 15. Divide-by-Three Circuit Waveforms

8.4 Device Functional Modes

Table 1. Function Table

RESET

OUTPUT

DISCHARGE SWITCH

Low

Irrelevant

Irrelevant

Low

On

High

Irrelevant

High

Off

High

Low

On

High

As previously established

(1)

Voltage levels shown are nominal.

12

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