A series circuit is one in which electric current ( I ) travels along a closed path that does not split apart:
*** Note: Conventional current consists of positive charges that flow from the positively charged anode to the negatively charged cathode. In reality, negatively charged electrons flow in the opposite direction. ***
The diagram, as depicted, is incorrect. To see why, let’s look at the equation for Ohm’s Law:
( V / R ) = I
Conductors offer very little resistance to electron flow. As a consequence, if resistance within a circuit is too low, the current that traverses the system will be too high. Within the field of electronics, this circumstance is referred to as a “ shorted circuit. “ Under the right ( or wrong ) conditions, a short circuit is not just dangerous to humans; such a current can do irreparable and costly damage to the system at hand.
The simplest direct current ( DC ) system is one in which a single resistor ( R ) is situated along the closed electrical pathway:
The circuit resistor establishes inertia within the system. As a consequence, the current no longer approaches a theoretically infinite value. Electrons that travel through such a resistor do so at the expense of work ( W ) that is performed on or within it; thus, a resistor can be an electric motor, heater, computer, or a wide array of other electrical devices. The current eventually reaches its destination at a lower energy state.
It is useful to think of the energy within a series circuit as currency. If a dollar is spent within a dollar store, it could be used to purchase a single item that costs a dollar. Likewise, the same unit of money could be used to purchase two items valued at $0.50/each or four items valued at $0.25/each. Analogous to this is a DC source of current that deposits energy in accordance to how many resistors it encounters. Adding or taking resistors from a series circuit will influence how energy is deposited in each resistor, but the net amount of energy per coulomb of charge that crosses the circuit will be the same. For this reason, the resistors within a series circuit are oftentimes referred to as “ voltage dividers “ within the field of electronics. Furthermore, real-world electrical systems lose energy in the form of heat, light, and sound:
Q: A 12 V source provides current to a series circuit. Initially, the circuit has a single resistor through which a 12 V drop occurs. If an identical resistor is added to the circuit, what voltage drop will occur at each resistor?
A: 6 V
RENAISSANCE PHYSICS 