user77534: I'm using a 74HC595N shift register to light up 8 LEDs but for some reason they won't turn on even though current is flowing through all of them. I provided an image of my circuit below, there is a test LED for checking current flow:

I am using a 9A103G resistor network to connect all the LEDs to a common ground. I have tried this with 8 individual 330 ohm resistors in the past but the result is the same, and every time the problem was with the ground wire, current is not flowing through it even though all the resistors I've used showed that current was flowing through them (see below):

The following image shows the same test LED not lighting up when connected to the common ground pin of the resistor network:

I could use some help fixing this issue because it is preventing me from using shift registers for future projects (this only happens when I use shift registers) - I would like to know what is causing this problem so I can avoid it later on. Thanks in advance!

user8583: (Just to illustrate what Majenko is saying.)
This is the inside of a breadboard:

All your connections are on one side of that; you've tied everything to a single point.

77534: <p>I'm using a 74HC595N shift register to light up 8 LEDs but for some reason they won't turn on even though current is flowing through all of them. I provided an image of my circuit below, there is a test LED for checking current flow:</p>
<p><a href="https://i.stack.imgur.com/lHNmZ.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lHNmZ.jpg" alt="This is my circuit" /></a></p>
<p>I am using a 9A103G resistor network to connect all the LEDs to a common ground. I have tried this with 8 individual 330 ohm resistors in the past but the result is the same, and every time the problem was with the ground wire, current is not flowing through it even though all the resistors I've used showed that current was flowing through them (see below):</p>
<p><a href="https://i.stack.imgur.com/h1Zg2.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/h1Zg2.jpg" alt="Current going through resistor network" /></a></p>
<p>The following image shows the same test LED not lighting up when connected to the common ground pin of the resistor network:</p>
<p><a href="https://i.stack.imgur.com/WfdOw.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WfdOw.jpg" alt="No current going through ground wire" /></a></p>
<p>I could use some help fixing this issue because it is preventing me from using shift registers for future projects (this only happens when I use shift registers) - I would like to know what is causing this problem so I can avoid it later on. Thanks in advance!</p>
 8583: <p>(Just to illustrate what Majenko is saying.)</p>
<p>This is the inside of a breadboard:</p>
<p><a href="https://i.stack.imgur.com/ACPzF.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/ACPzF.jpg" alt="enter image description here" /></a></p>
<p>All your connections are on one side of that; you've tied everything to a single point.</p>
