Want to know how current and voltage behave in different... Show more
Physics254 views·Updated May 23, 2026·2 pagesUnderstanding I/V Characteristics: Physics Practical
Lucía @luttior
1
of 2
Setting Up Your I/V Characteristics Investigation
You'll be investigating how current and voltage relate in different circuit components using some basic equipment. Your circuit needs a battery, the component you're testing, an ammeter (measures current through the component), a voltmeter (measures potential difference across the component), and a variable resistor to change the values.
The method is straightforward: record the voltage and current readings, then adjust the variable resistor to get different values. Don't forget to reverse the battery direction halfway through - this gives you negative readings and shows the complete picture of how your component behaves.
When you plot your results for a resistor, you'll get a straight line through zero. This proves that current is directly proportional to potential difference - a key characteristic of ohmic conductors. The line stays straight even when you reverse the battery direction.
Top Tip: Keep your circuit connected for short periods only, as heating can change your resistor's behaviour and mess up your results.
2
of 2
Testing Different Components
Temperature matters hugely in these experiments. If your resistor gets hot from being connected too long, your straight-line graph will curve instead - the resistance increases with temperature and ruins the proportional relationship.
Filament lamps behave completely differently. Your graph won't be a straight line because as current increases, the filament heats up and its resistance increases. This creates a curved graph that shows current is not proportional to potential difference.
Diodes need special care because they're easily damaged by high current. Always add an extra resistor to protect the diode and keep currents low. You'll need a sensitive milliammeter instead of a regular ammeter since the currents are so small.
Exam Alert: Remember that only resistors at constant temperature give straight-line graphs - filament lamps and diodes create curved graphs due to their changing resistance.
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Physics254 views·Updated May 23, 2026·2 pagesUnderstanding I/V Characteristics: Physics Practical
Lucía @luttior
Want to know how current and voltage behave in different electrical components? This practical investigation shows you how to measure and graph the relationship between current and voltage in resistors, filament lamps, and diodes - essential skills for your physics... Show more
1
of 2Sign up to see the content. It's free!
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Setting Up Your I/V Characteristics Investigation
You'll be investigating how current and voltage relate in different circuit components using some basic equipment. Your circuit needs a battery, the component you're testing, an ammeter (measures current through the component), a voltmeter (measures potential difference across the component), and a variable resistor to change the values.
The method is straightforward: record the voltage and current readings, then adjust the variable resistor to get different values. Don't forget to reverse the battery direction halfway through - this gives you negative readings and shows the complete picture of how your component behaves.
When you plot your results for a resistor, you'll get a straight line through zero. This proves that current is directly proportional to potential difference - a key characteristic of ohmic conductors. The line stays straight even when you reverse the battery direction.
Top Tip: Keep your circuit connected for short periods only, as heating can change your resistor's behaviour and mess up your results.
2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Testing Different Components
Temperature matters hugely in these experiments. If your resistor gets hot from being connected too long, your straight-line graph will curve instead - the resistance increases with temperature and ruins the proportional relationship.
Filament lamps behave completely differently. Your graph won't be a straight line because as current increases, the filament heats up and its resistance increases. This creates a curved graph that shows current is not proportional to potential difference.
Diodes need special care because they're easily damaged by high current. Always add an extra resistor to protect the diode and keep currents low. You'll need a sensitive milliammeter instead of a regular ammeter since the currents are so small.
Exam Alert: Remember that only resistors at constant temperature give straight-line graphs - filament lamps and diodes create curved graphs due to their changing resistance.
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