Summary: Physics
- This + 400k other summaries
- A unique study and practice tool
- Never study anything twice again
- Get the grades you hope for
- 100% sure, 100% understanding
Read the summary and the most important questions on Physics
-
Electricity
This is a preview. There are 6 more flashcards available for chapter 01/05/2017
Show more cards here -
Describe the I-V characteristic of a diode
- Current can only flow in one direction
- Forward bias allows current flow
- There is a threshold voltage for the forward direction
- Reverse bias has a v high resistance so no current can flow -
Describe the I-V characteristics of a metallic conductor
- Directly proportional relationship through the origin
- Constant temperature, is an Ohmic conductor
- 1/Gradient = resistance
- Shallower gradient means higher resistance -
Describe the I-V characteristics of a filament lamp
- Lamp is coiled up wire (metallic conductor) but is not Ohmic
- Current flowing increases the temperature so its resistance increases -
Describe the I-V and resistance characteristics of an NTC thermistor
- A resistor with resistance depending on temperature
RESISTANCE
- NTC (negative temperature coefficient) means resistance decreases with increasing temperature
- More energy means more e- can escape, more charge carriers, current increases
I-V- Voltage increases, current increases
- Current increases, temperature increases and resistance decreases
- More current can flow, graph curves upwards -
Describe the resistance of a Light-Dependant Resistor (LDR)
- Greater light intensity, lower resistance
- Light gives energy to release e-
- Higher current, lower resistance -
What is the component necessary to measure I-V characteristics?
Variable resistor
- Alters potential difference and current to show how resistance varies -
Draw the I-V characteristics for a diode
Current only flows in forward bias -
Draw the I-V characteristic of a metallic conductor
Directly proportional through origin -
Draw the I-V characteristic for a filament lamp
Through origin -
Draw the I-V characteristics for an NTC thermistor
More current flows with temp increase
- Higher grades + faster learning
- Never study anything twice
- 100% sure, 100% understanding