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NE555: Start up time

Kuramochi Tadahiko
Guru 28715 points
Part Number: NE555

Hi,

My customer would like to calculate time from power supply turn-on to stable output.

"?" on the attached file is the time.

Can we calculate this?NE555.pdf

Best Regards,

Kuramochi

  • 0
    TI__Guru**** 165326 points

    Kuramochi-san,

    Before power up the timing capacitor is discharged. Therefore at power up the output will go high immediately (within a couple microseconds). The first high output pulse will be 58% longer than the other high pulses after that. The reason is that the capacitor start charging from 0V on the first high  pulse and starts at 1/3*VCC for the rest.

    Like this

    Is the control pin open?