This is a basic question but I am a little bit confused on how to interpret this diagram. What are the symbols that are present in this diagram? What happens when there is current running through the circuit?
I am not an electrical engineer but this popped up in one of my software engineering courses.
Schematics like that use a lot of abbreviation. Let me give you the full version:
simulate this circuit – Schematic created using CircuitLab
The little ground symbol at the bottom of your schematic is doing a lot of work. \$V_{CC}\$, \$V_{in}\$, and \$V_{out}\$ are all implicitly defined relative to ground. Furthermore, it is implied by context that \$V_{CC}\$ is constant (DC), while \$V_{in}\$ can change (AC, but not necessarily a sinusoid -- the term "AC" is overloaded).
As others have mentioned, the circuit is a simple inverter (a NOT gate). When \$V_{in} = 0 \mathrm V\$, the transistor is off, and the output is connected to \$V_{CC}\$ through the resistor \$R_L\$ \$(V_{out} = V_{CC})\$. When \$V_{in} = V_{CC}\$, the transistor is on (top and bottom terminals connected together), which connects \$V_{out}\$ to ground \$(V_{out} = 0 \mathrm V)\$.
It is implied that \$V_{out}\$ would be connected to another component. In a logic circuit, it would act as the \$V_{in}\$ to another transistor.
Labeling the load current \$I_L\$ makes it easier to talk about things like power dissipation and maximum output current, but I doubt you'll need to worry about those.
This is a really simplistic transistor amplifier or switch circuit (in a computer course it's more likely they mean it to be a switch).
When the voltage at \$V_{in}\$ is below a certain point (roughly 0.6 V) the transistor will be turned off and \$V_{out}\$ will be close to \$V_{CC}\$, when the input voltage goes above that the transistor starts to conduct drawing current through \$R_L\$, when the voltage is high enough to cause the transistor to saturate \$V_{out}\$ will be near ground potential (0 V).
So by changing the input signal from a low to high, the output will go from high to low, and you have a basic inverter circuit.
What are the symbols that are present in this diagram?
There is a bipolar junction transistor (BJT) and a resistor. There are also wires, and labels for the designator of the resistor, the node voltages, and one of the branch currents in the circuit.
What happens when there is current running through the circuit?
Roughly, assuming you have the circuit biased to keep the BJT in the forward-active operating mode, increasing \$V_{in}\$ increases the load current (\$I_L\$) and lowers the ouput voltage (\$V_{out}\$), and vice versa.
Since it seems your electronics fundamentals is something your researching at the moment, I would look into the area of microelectronics. There will be many YouTube channels that go over this information, which will be much more interesting than the way we (I) had to learn, which is an absolutely massive textbook!
Some keywords/investigative areas to search:
Khan academy probably has some good videos, and will be a good place to go!
To go over all the details would be quite cumbersome, but what you have there is a voltage source VCC" that connects to a Resistor "RL", which then connects the the collector pin of a NPN bipolar junction transistor (BJT). The emitter pin of the BJT (the one with an arrow attached to it), then connects to what is commonly called ground. Another voltage source "Vin", connects the base pin of the BJT.
