Series Circuit
A series circuit is one with all the loads in a row. Like links in a chain. There is only ONE path for the electricity to flow. If this circuit was a string of light bulbs, and one blew out, the remaining bulbs would turn off.
NOTE: The squiggly lines in the diagram are the symbol for Resistors. The parallel lines are the symbol for a battery.
Parallel Circuit
A parallel circuit is one that has two or more paths for the electricity to flow. In other words, the loads are parallel to each other. If the loads in this circuit were light bulbs and one blew out there is still current flowing to the others as they are still in a direct path from the negative to positive terminals of the battery.
Combination Circuit
A combination circuit is one that has a "combination" of series and parallel paths for the electricity to flow. Its properties are a synthesis of the two. In this example, the parallel section of the circuit is like a sub-circuit and actually is part of an over-all series circuit.
A series circuit is one with all the loads in a row. Like links in a chain. There is only ONE path for the electricity to flow. If this circuit was a string of light bulbs, and one blew out, the remaining bulbs would turn off.
NOTE: The squiggly lines in the diagram are the symbol for Resistors. The parallel lines are the symbol for a battery.Parallel Circuit
A parallel circuit is one that has two or more paths for the electricity to flow. In other words, the loads are parallel to each other. If the loads in this circuit were light bulbs and one blew out there is still current flowing to the others as they are still in a direct path from the negative to positive terminals of the battery.
Combination CircuitA combination circuit is one that has a "combination" of series and parallel paths for the electricity to flow. Its properties are a synthesis of the two. In this example, the parallel section of the circuit is like a sub-circuit and actually is part of an over-all series circuit.
VOLTAGE, CURRENT & RESISTANCE EXPLAINED
Voltage
Voltage is the electrical force, or "pressure", that causes current to flow in a circuit. It is measured in VOLTS (V or E). Take a look at the diagram. Voltage would be the force that is pushing the water (electrons) forward.
Voltage is the electrical force, or "pressure", that causes current to flow in a circuit. It is measured in VOLTS (V or E). Take a look at the diagram. Voltage would be the force that is pushing the water (electrons) forward.
Current
Current is the movement of electrical charge - the flow of electrons through the electronic circuit. Current is measured in AMPERES (AMPS, A or I). Current would be the flow of water moving through the tube (wire).
Current is the movement of electrical charge - the flow of electrons through the electronic circuit. Current is measured in AMPERES (AMPS, A or I). Current would be the flow of water moving through the tube (wire).
Resistance
Resistance is anything that causes an opposition to the flow of electricity in a circuit. It is used to control the amount of voltage and/or amperage in a circuit. Everything in the circuit causes a resistance (even wire). It is measured in OHMS (W).
Resistance is anything that causes an opposition to the flow of electricity in a circuit. It is used to control the amount of voltage and/or amperage in a circuit. Everything in the circuit causes a resistance (even wire). It is measured in OHMS (W).
In simpler terms, Ohm’s Law means:
1) A steady increase in voltage, in a circuit with constant resistance, produces a constant linear rise in current.
1) A steady increase in voltage, in a circuit with constant resistance, produces a constant linear rise in current.
2) A steady increase in resistance, in a circuit with constant voltage, produces a progressively (not a straight-line if graphed) weaker current.
Ohm's Law is a formulation of the relationship of voltage, current, and resistance, expressed as: 
Where:
V is the Voltage measured in volts
I is the Current measured in amperes
R is the resistance measured in Ohms Therefore: Volts = Amps times Resistance
V is the Voltage measured in volts
I is the Current measured in amperes
R is the resistance measured in Ohms Therefore: Volts = Amps times Resistance
An easy way to remember the formulas is by usingthis diagram. 
To determine a missing value, cover it with your finger. The horizontal line in the middle means to divide the two remaining values. The "X" in the bottom section of the circle means to multiply the remaining values.
• If you are calculating voltage, cover it and you have I X R left (V= I times R).
• If you are calculating amperage, cover it, and you have V divided by R left (I=V/R).
• If you are calculating resistance, cover it, and you have V divide by I left (R=V/I).
• If you are calculating resistance, cover it, and you have V divide by I left (R=V/I).
Note: The letter E is sometimes used instead of V for voltage.
