2a.6 - Current, potential difference & Circuit symbols Flashcards
What is current?
The flow of electric charge round the circuit
What is potential difference?
The driving force that pushes the current round the circuit
The greater the resistance across a component, the smaller…
… the current that flows
What does a resistor look like?
A box with no line
What does a variable resistor look like?
A line with an arrow through it
What does a diode look like?
A circle one with a triangle in it and a line at the end of it
What does an LDR look like?
A squished fuse (smaller box) with a circle round it and two arrows facing the circle on the left side
What does a thermistor look like?
A fuse with a weird tic through it
What does an LED look like?
A circle one with a triangle in it with a line at the end (twins with a diode) with two arrows facing away from the circle
What is an ammeter? (2)
- Measures the current
- Must be placed in series
What is a volt meter? (2)
- Measures the potential difference across the component
- Placed in parallel around the component under test
What do the graphs for resistors look like?
- The current through a resistor is directly proportional to potential difference
What do the graphs for filament lamps look like?
As the temperature of the filament increases, the resistance increases, so the graph is a curve
What do the graphs for diodes look like?
Current will only flow through a diode in one direction. The diode has a very high resistance in the opposite direction. The graph is a straight line until it curves suddenly.
What increases resistance?
Temperature
