Simple Circuits

OP51 Simple Circuits

In order for a current to flow a number of things need to be in place,

  1. a power source
  2. a path, or circuit, often broken by a switch
  3. a load, (something to use up the energy of the electricity)
  4. a device to measure the state of the electricity

Series Circuit

A Series circuit means the electricity flows from one terminal (-ive) to the other terminal through all the Components (in this case bulbs)

As the electricity flows across each component the potential difference (voltage) drops each time

Parallel Circuit

Parallel Circuits provide different routes for the electricity to flow from one side to the other.

The Voltage across each bulb is the same as if there was only one bulb.

So you should set up both these circuits. Note that the schematic diagrams above do not really look like the actual thing, there are no right angles in the wires.

What differences do you notice between the 2 different circuits ?

  1. Parallel bulbs are brighter
  2. Parallel circuit remains on even if a bulb is removed / broken
  3. Parallel circuits need more wires / connections

What happens if you disconnect a wire in the series circuit ?

What happens if you disconnect a wire in the parallel part of the parallel circuit ?

The Voltage drop is shared in a series circuit and so the voltage, so the voltages drop from its high point to ground (or zero potential)

A really nice page here on series and parrallel circuits (for the advanced learner)

The Multimeter is the modern way of measuring quantities about electricity around the circuit.

V = Voltage

A = Current

R = Resistance

Voltage is the attraction of electrons to a positive charge. The bigger the voltage the bigger the attraction

Can be thought of as the greater difference in height as in a river flowing to the sea

Current is the amount of electrons passing a point per second. Current is given the symbol I and is measured in Amperes (Amps).

This current can be though of as the speed of flow of a river.