Simple 555 timer

Thread Starter

sparjan

Joined Oct 21, 2010
2
Hello i'm beginner in electronics…and
i want to create a simple NE555 timer.

First in normal mode the pin3 output should be high.
When pin 2 is triggered (from the other circuit), then the pin3(output) should be low for 30 seconds and after the 30 seconds completes the pin3 should be continuously high.

since i'm beginner plz link me to schematics....
 

tracecom

Joined Apr 16, 2010
3,944
What you want is called a monostable circuit, also known as a one-shot. But, in addition to a normal 555 one-shot, you will need a transistor inverter on the output of the 555. I suggest you build the one-shot first, get it working, and then add the transistor inverter circuit. The transistor can be any common NPN, such as a 2N3904, 2N2222, or BC547.

Are you planning to build this on a solderless breadboard? What is your power supply going to be, and what is its voltage? What are you going to drive with this circuit?
 

eman12

Joined Oct 26, 2007
41
Hello i'm beginner in electronics…and
i want to create a simple NE555 timer.

First in normal mode the pin3 output should be high.
When pin 2 is triggered (from the other circuit), then the pin3(output) should be low for 30 seconds and after the 30 seconds completes the pin3 should be continuously high.

since i'm beginner plz link me to schematics....
Hello Sparjan,

In the net there are a lot of circuits about so called "Monosatable" circuits:
http://www.google.com/#fp=bb3d3dbe2c8a92ac&q=monostable++555

Cheers
 
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