Download U4D2 03.09 Notes

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Power MOSFET wikipedia, lookup

Operational amplifier wikipedia, lookup

Music technology wikipedia, lookup

Nanogenerator wikipedia, lookup

Galvanometer wikipedia, lookup

Surge protector wikipedia, lookup

Multimeter wikipedia, lookup

Resistive opto-isolator wikipedia, lookup

TRIAC wikipedia, lookup

Rectiverter wikipedia, lookup

Nanofluidic circuitry wikipedia, lookup

Electric charge wikipedia, lookup

Current mirror wikipedia, lookup

Opto-isolator wikipedia, lookup

Ohm's law wikipedia, lookup

Electric Current
• Electric current is the movement of electric charge
• Although it is the electrons that actually move, by
convention, the direction that electric current
flows is the direction that positive charge moves
• Electric charge moves in response to a difference
in electric potential between two locations
• The charge moves (electric current flows) from
the location with higher potential to the location
with lower potential
Electric Circuits
• A pathway of charge movement is called an
“electric circuit”
• We are most familiar with electric current
moving in a circuit made of wire, but that is
not a requirement
• An electric circuit must be “closed” for current
to flow – the pathway must be continuous
• If a gap exists in a circuit, we say that the circuit
is “open” – electric current does not flow
Ohm’s Law
• The amount of current flowing in a circuit is
• directly proportional to the potential difference
• and inversely proportional to the resistance
• The equation for this relationship is “I = V/R”
• Current flow (I) is measured in “amperes”
• Potential difference (V) is measured in “volts”
• Resistance (R) is measured in “ohms”
• This is “Ohm’s Law” – generally written V = I x R
• The difference in electric potential that causes
current flow is usually called the “voltage”
• Voltage can come from a battery or a generator
• We will look mostly at direct current (DC) circuits
• Current flow will be in one direction
• Voltage will be provided by a battery
• The “resistance” in an electric circuit is all of the
things that impede the flow of current
• Sometimes these are devices that use the
electrical energy such as lights or appliances
• Sometimes these are devices, called resistors,
that are used to limit the amount of current
• Even the length, temperature, and diameter of
the wire can affect the resistance in a circuit
• long, hot, thin wires have greater resistance
than short, cool, thick wires