Ohm's Law states that current flow in a circuit varies in direct proportion to changes in voltage, and in inverse proportion to the changes in resistance.
An ammeter is connected in series. A voltmeter is connected in parallel. With an ohmmeter, the item to be tested must first be disconnected from its circuit.
In a parallel circuit, all components are connected directly to the voltage supply. If one of the connections or components fails in a parallel circuit, current continues to flow through the rest.
Wire size is very important for the correct operation of electrical circuits. Selecting too small a gauge wire for an application will adversely effect the operation of the circuit. Selecting too large a gauge increases costs and weight.
Fiber optics are long, thin strands of very pure glass about the diameter of a human hair. They can be arranged in bundles and are called optical cables. Light signals can be transmitted along the cable over very long distances.
