Electrical circuits Flashcards
WHat symbol is I
Current
what is Current a measure of
The flow of electrons around the circuit
What is current measured by?
Amperes (amps)
What symbol is V
Potential difference
What is potential difference
The force driving the flow of electrons provided by cell
What is PD measured in?
Voltage (volts)
What symbol is R
Resistance
What is resistance?
Everything that resists or opposes the flow of electrons
What is resistance measured in?
Ohms
If we increase the temp what will happen to the resistor?
also increases
filament lamp graph reading
- current increases = temp increase
- causes the resistance to increase
- so less current flows per unit pd
Diode graph reading
- current flows in one direction
- has very high resistance in reverse
direction
Fixed resistor graph
- Current is directly proportional to pd
Why does the resistance increase when the temp does?
All of the ions in the metal vibrate faster making it harder for electrons to pass along the wire
What is charge a measure of
The total current that flowed within a certain period of time
What is charge measured in?
Coulombs (C)
What are fuses used for?q
Break the circuit if too much current
What could LDR (light depedant resistors) be used for?
- automatic night-lights
- burglar alarms
What could thermistor be used for?
- Care engine
- electronic thermostats
What is a downside of a series circuit?
if any of the component in the circuit is removed or disconnected, the circuit breaks and stops
potential difference in a series circuit
PD is shared across all the components
current in a series circuit
same everywhere in the circuit
ohms law
components with a greater resistance, will always have a higher share of the voltage
series circuit
Only has a single loop
Parallel circuit
Has more than one loop
pD in parallel circuit
the same across all components
current in parallel circuit
Shared across all components
resistance in parallel circuit
Loops with a greater resistance has a lower share of the current
