# NE555 configuration

#### Eudécio Gabriel

Joined Jun 24, 2018
15
I already have a NE555 connected properly in my breadboard in astable configuration. I want to generate a pulse with a period equal to 0.1 seconds. What values of resistances should I use given that I have a 100nF capacitor.

#### killivolt

Joined Jan 10, 2010
756
I already have a NE555 connected properly in my breadboard in astable configuration. I want to generate a pulse with a period equal to 0.1 seconds. What values of resistances should I use given that I have a 100nF capacitor.
Check this out......

NE555

#### dl324

Joined Mar 30, 2015
10,488
What values of resistances should I use given that I have a 100nF capacitor.
Since you've selected a capacitor value, calculating period is straightforward. Just remember to consider component tolerance.
$$\small t = 1.1RC => R = \frac{t}{1.1C}$$

Or you can use this graph from the datasheet for quick approximations:

There's a typo. There is no RB.

EDIT: cleaned up tex block.

Last edited:

#### Dodgydave

Joined Jun 22, 2012
9,071
Try 910K ohms....

#### Audioguru

Joined Dec 20, 2007
11,249
First you said you built an NE555 astable that is a continuously running oscillator. Then you said you want to generate "a pulse" which is a triggered monostable NE555 circuit. The monostable circuit is shown above.
What will trigger your monostable? It must be a momentary pulse to 0V to pin 2.