I am a newbie electronics learner and trying my hands on 555 timer to get it running in the monostable mode. Am trying the circuit as in the attached diagram. I am just unable to get the LED blink. I have tried the following troubleshooting steps:
- Tried with different LEDs. Made sure they work.
- Made sure replacing C1 capacitor with different values to ensure the capacitor is not faulty.
- Removing and replacing ceramic capacitor at pin 5 to make sure its not causing any issues.
- Trying various resistor and capacitor combinations; making sure that the pulse is not too short to be visible.
- Tried with 5 different 555 timers to eliminate the possibility of a faulty chip. Though they were all bought from the same vendor at the same time.
Given the reputation of the 555 timers and their proven history, most likely I am doing something wrong here. Can some one please suggest what could be missing? Ignore the spiral at the bottom of the picture, my two year old is learning with me how to draw electronic circuits.
Adding the pictures of my setup on breadboard. Battery is 9V, R1 - the resistor on PIN 7 is 96 K Ohms and the cylindrical capacitor is 1000 micro farads. There are 3 LEDs on the board. The two lighted LEDs on the power rails show that both the rails have power. The third one, connected to the output, has its negative terminal connected to ground power rail and positive terminal connected to pin 3 (output) of the timer for pulse. This LED is OFF in pictures and is not getting getting ON; but I have successfully tested it before and after taking the pictures; so it's a working LED. You can also see some other 555 timers at the bottom which I am trying alternatively.
I have tried it two ways.
Picture 1 and 2 (zoomed) show the setup where I am using a button to trigger the pin 2 of the timer.
Picture 3 shows the second way where instead of using a button, I am manually inserting the grey wire on pin 2 into the negative power rail for a brief time period to create the trigger.
Picture 4 just shows that the cylindrical capacitor's negative terminal is connected to the negative power rail.
Picture 1: Using a switch to generate trigger:
Picture 2: Using a switch to generate trigger - Zoomed:
Picture 3: Using a loose wire to generate trigger:
Picture 4: Capacitor's negative terminal: