# NE555 configuration

Discussion in 'General Electronics Chat' started by Eudécio Gabriel, Mar 31, 2019.

1. ### Eudécio Gabriel Thread Starter New Member

Jun 24, 2018
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0
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.

2. ### killivolt Distinguished Member

Jan 10, 2010
679
994
Check this out......

NE555

3. ### dl324 AAC Fanatic!

Mar 30, 2015
8,714
2,106
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: Mar 31, 2019
4. ### Dodgydave AAC Fanatic!

Jun 22, 2012
8,263
1,440
Try 910K ohms....

5. ### Audioguru Expert

Dec 20, 2007
11,249
1,349
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.