Simple 555 timer

Discussion in 'General Electronics Chat' started by sparjan, Aug 22, 2013.

  1. sparjan

    Thread Starter New Member

    Oct 21, 2010
    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....
  2. tracecom

    AAC Fanatic!

    Apr 16, 2010
    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?
  3. eman12

    Active Member

    Oct 26, 2007
    Hello Sparjan,

    In the net there are a lot of circuits about so called "Monosatable" circuits: