No output from 556 timer

Question

I've attempted to set up a 556 timer on a breadboard. I bought two 556 timers because the project I will be using it in requires 3 timers, and I wanted to be cost effective.

I have followed a tutorial online about how to wire it on a breadboard, and for right now I am only using one of the timers on the 556 chip. Unfortunately, there is no output going into the LED, i.e it isn't flashing like it should be. I've read the data sheet, turned my LED and capacitor around, and tried a second chip that I have. No luck so far

Have I wired it incorrectly, or did I just have bad luck and end up with 2 busted chips?

Thanks for your help

Here's a picture of my breadboard:

Link to 556 datasheet

Answer 1

Even if the picture is not very clear I can guess you're trying to implement the classic astable circuit, using timer 2.

However, I find the following issues:

1. You are not connecting the reset (pin 10) to VCC (even if internally is connected to the base of a PNP transistor, so leaving it open might not cause a reset).
2. The LED is likely connected to the same row (unless you soldered the resistor to its cathode), but we cannot see this from the picture.
3. The capacitor has its negative terminal toward threshold and trigger: the negative terminal should go to GND.
4. Maybe is not shown, but from the picture we cannot see if you are connecting the ground (blue line) of the right part of the breadboard, to the ground of the left part of the board.