Karl Gega Posted May 25, 2005 Report Share Posted May 25, 2005 I have projected this timer and built it.But the output stays always High, i don't know what's wrong with it?The cap is 2200uF and the resistor is 10k. I have also tried with a 100uF cap but still no change.Any help? Quote Link to comment Share on other sites More sharing options...
David Bridgen Posted May 25, 2005 Report Share Posted May 25, 2005 Pin 2 needs to be "pulled up", so connect a resistor from it to the positive supply. Quote Link to comment Share on other sites More sharing options...
Karl Gega Posted May 25, 2005 Author Report Share Posted May 25, 2005 Still the output stays high. Quote Link to comment Share on other sites More sharing options...
David Bridgen Posted May 25, 2005 Report Share Posted May 25, 2005 Hmmm .....The switch on the trigger pin is a momentary action one? The circuit looks fine otherwise (with a pull up on pin 2). Quote Link to comment Share on other sites More sharing options...
Karl Gega Posted May 26, 2005 Author Report Share Posted May 26, 2005 Yes the switch is a momentary action one.It is possible that the IC has gone bad because in the beggining i changed the powerwires by mistake (connected ground to Vcc snd Vcc to ground ) and IC heat up so much that it couldn't be touched with hand (it might have remaind in that state for two minutes). Should i replace it? Or it is ok.Thank you for your time. Quote Link to comment Share on other sites More sharing options...
David Bridgen Posted May 26, 2005 Report Share Posted May 26, 2005 Ah. Yes Karl, replace it. Quote Link to comment Share on other sites More sharing options...
Karl Gega Posted May 28, 2005 Author Report Share Posted May 28, 2005 I have done all the changes suggested here and came to this one. I will build later. Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 28, 2005 Report Share Posted May 28, 2005 Hi Karl,With the diode across the relay coil backwards, the 555 IC will burn again. I mentioned other necessary changes in your other topic. ;D Quote Link to comment Share on other sites More sharing options...
Karl Gega Posted May 31, 2005 Author Report Share Posted May 31, 2005 What about this one? Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 31, 2005 Report Share Posted May 31, 2005 The diode across the relay coil (in parallel) is still backwards. Quote Link to comment Share on other sites More sharing options...
Guest Alun Posted May 31, 2005 Report Share Posted May 31, 2005 I've corrected it for you. Quote Link to comment Share on other sites More sharing options...
Karl Gega Posted June 4, 2005 Author Report Share Posted June 4, 2005 Thank you Alun Quote Link to comment Share on other sites More sharing options...
login
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.